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>

README.md

@@ -1,6 +1,6 @@
 # Pjax
 
-[![Build Status](https://img.shields.io/travis/MoOx/pjax.svg)](https://travis-ci.org/MoOx/pjax)
+[![Build Status](https://img.shields.io/travis/MoOx/pjax.svg)](https://travis-ci.org/MoOx/pjax).
 
 > Easily enable fast AJAX navigation on any website (using pushState() + XHR)
 

package-lock.json

@@ -439,30 +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",
@@ -7962,16 +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",