Bump shell-quote from 1.6.1 to 1.7.3

Bumps [shell-quote](https://github.com/substack/node-shell-quote) from 1.6.1 to 1.7.3.
- [Release notes](https://github.com/substack/node-shell-quote/releases)
- [Changelog](https://github.com/substack/node-shell-quote/blob/master/CHANGELOG.md)
- [Commits](https://github.com/substack/node-shell-quote/compare/1.6.1...1.7.3)

---
updated-dependencies:
- dependency-name: shell-quote
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "pjax",
-  "version": "0.2.7",
+  "version": "0.2.8",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -298,6 +298,7 @@
       "resolved": "https://registry.npmjs.org/align-text/-/align-text-0.1.4.tgz",
       "integrity": "sha1-DNkKVhCT810KmSVsIrcGlDP60Rc=",
       "dev": true,
+      "optional": true,
       "requires": {
         "kind-of": "^3.0.2",
         "longest": "^1.0.1",
@@ -438,30 +439,12 @@
       "integrity": "sha1-jCpe8kcv2ep0KwTHenUJO6J1fJM=",
       "dev": true
     },
-    "array-filter": {
-      "version": "0.0.1",
-      "resolved": "https://registry.npmjs.org/array-filter/-/array-filter-0.0.1.tgz",
-      "integrity": "sha1-fajPLiZijtcygDWB/SH2fKzS7uw=",
-      "dev": true
-    },
     "array-find-index": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/array-find-index/-/array-find-index-1.0.2.tgz",
       "integrity": "sha1-3wEKoSh+Fku9pvlyOwqWoexBh6E=",
       "dev": true
     },
-    "array-map": {
-      "version": "0.0.0",
-      "resolved": "https://registry.npmjs.org/array-map/-/array-map-0.0.0.tgz",
-      "integrity": "sha1-iKK6tz0c97zVwbEYoAP2b2ZfpmI=",
-      "dev": true
-    },
-    "array-reduce": {
-      "version": "0.0.0",
-      "resolved": "https://registry.npmjs.org/array-reduce/-/array-reduce-0.0.0.tgz",
-      "integrity": "sha1-FziZ0//Rx9k4PkR5Ul2+J4yrXys=",
-      "dev": true
-    },
     "array-union": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/array-union/-/array-union-1.0.2.tgz",
@@ -1019,7 +1002,7 @@
       "dependencies": {
         "callsites": {
           "version": "2.0.0",
-          "resolved": "http://registry.npmjs.org/callsites/-/callsites-2.0.0.tgz",
+          "resolved": "https://registry.npmjs.org/callsites/-/callsites-2.0.0.tgz",
           "integrity": "sha1-BuuE8A7qQT2oav/vrL/7Ngk7PFA=",
           "dev": true
         }
@@ -1185,7 +1168,7 @@
         },
         "slice-ansi": {
           "version": "0.0.4",
-          "resolved": "http://registry.npmjs.org/slice-ansi/-/slice-ansi-0.0.4.tgz",
+          "resolved": "https://registry.npmjs.org/slice-ansi/-/slice-ansi-0.0.4.tgz",
           "integrity": "sha1-7b+JA/ZvfOL46v1s7tZeJkyDGzU=",
           "dev": true
         },
@@ -2338,7 +2321,7 @@
         },
         "load-json-file": {
           "version": "2.0.0",
-          "resolved": "http://registry.npmjs.org/load-json-file/-/load-json-file-2.0.0.tgz",
+          "resolved": "https://registry.npmjs.org/load-json-file/-/load-json-file-2.0.0.tgz",
           "integrity": "sha1-eUfkIUmvgNaWy/eXvKq8/h/inKg=",
           "dev": true,
           "requires": {
@@ -4151,7 +4134,7 @@
     },
     "jsonfile": {
       "version": "2.4.0",
-      "resolved": "http://registry.npmjs.org/jsonfile/-/jsonfile-2.4.0.tgz",
+      "resolved": "https://registry.npmjs.org/jsonfile/-/jsonfile-2.4.0.tgz",
       "integrity": "sha1-NzaitCi4e72gzIO1P6PWM6NcKug=",
       "dev": true,
       "requires": {
@@ -4392,7 +4375,7 @@
         },
         "globby": {
           "version": "6.1.0",
-          "resolved": "http://registry.npmjs.org/globby/-/globby-6.1.0.tgz",
+          "resolved": "https://registry.npmjs.org/globby/-/globby-6.1.0.tgz",
           "integrity": "sha1-9abXDoOV4hyFj7BInWTfAkJNUGw=",
           "dev": true,
           "requires": {
@@ -4405,7 +4388,7 @@
           "dependencies": {
             "pify": {
               "version": "2.3.0",
-              "resolved": "http://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
+              "resolved": "https://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
               "integrity": "sha1-7RQaasBDqEnqWISY59yosVMw6Qw=",
               "dev": true
             }
@@ -4685,7 +4668,8 @@
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/longest/-/longest-1.0.1.tgz",
       "integrity": "sha1-MKCy2jj3N3DoKUoNIuZiXtd9AJc=",
-      "dev": true
+      "dev": true,
+      "optional": true
     },
     "loud-rejection": {
       "version": "1.6.0",
@@ -5166,6 +5150,7 @@
           "version": "0.1.4",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "kind-of": "^3.0.2",
             "longest": "^1.0.1",
@@ -5976,7 +5961,8 @@
         "longest": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "loose-envify": {
           "version": "1.3.1",
@@ -7958,16 +7944,10 @@
       "dev": true
     },
     "shell-quote": {
-      "version": "1.6.1",
-      "resolved": "https://registry.npmjs.org/shell-quote/-/shell-quote-1.6.1.tgz",
-      "integrity": "sha1-9HgZSczkAmlxJ0MOo7PFR29IF2c=",
-      "dev": true,
-      "requires": {
-        "array-filter": "~0.0.0",
-        "array-map": "~0.0.0",
-        "array-reduce": "~0.0.0",
-        "jsonify": "~0.0.0"
-      }
+      "version": "1.7.3",
+      "resolved": "https://registry.npmjs.org/shell-quote/-/shell-quote-1.7.3.tgz",
+      "integrity": "sha512-Vpfqwm4EnqGdlsBFNmHhxhElJYrdfcxPThu+ryKS5J8L/fhAwLazFZtq+S+TWZ9ANj2piSQLGj6NQg+lKPmxrw==",
+      "dev": true
     },
     "shelljs": {
       "version": "0.5.3",
@@ -8386,9 +8366,9 @@
       }
     },
     "stringstream": {
-      "version": "0.0.5",
-      "resolved": "https://registry.npmjs.org/stringstream/-/stringstream-0.0.5.tgz",
-      "integrity": "sha1-TkhM1N5aC7vuGORjB3EKioFiGHg=",
+      "version": "0.0.6",
+      "resolved": "https://registry.npmjs.org/stringstream/-/stringstream-0.0.6.tgz",
+      "integrity": "sha512-87GEBAkegbBcweToUrdzf3eLhWNg06FJTebl4BVJz/JgWy8CvEr9dRtX5qWphiynMSQlxxi+QqN0z5T32SLlhA==",
       "dev": true
     },
     "strip-ansi": {