Updating dev dependencies and build dependencies

Closes #426

package.json

@@ -42,24 +42,27 @@
     "report-dir": "./reports/coverage"
   },
   "devDependencies": {
-    "browserify": "5.11.1",
-    "coveralls": "^2.13.1",
-    "gulp": "^3.9.1",
+    "browserify": "^16.5.2",
+    "coveralls": "^3.1.0",
+    "gulp": "^4.0.2",
     "gulp-gh-pages": "^0.5.4",
-    "gulp-jsdoc3": "^0.2.1",
-    "gulp-mustache": "0.4.0",
-    "gulp-rename": "1.2.0",
-    "gulp-uglify": "1.0.1",
+    "gulp-jsdoc3": "^3.0.0",
+    "gulp-mustache": "^5.0.0",
+    "gulp-rename": "^2.0.0",
+    "gulp-uglify": "^3.0.2",
     "ink-docstrap": "1.1.4",
     "jsdoc": "^3.4.0",
     "jshint": "0.9.0",
     "lodash": "^4.6.1",
-    "mocha": "^3.2.0",
+    "mocha": "^8.1.1",
     "node-minify": "*",
+    "nyc": "^15.1.0",
     "optimist": "0.3.5",
-    "sinon": "1.4.2",
+    "sinon": "^9.0.3",
     "through2": "2.0.0",
-    "vinyl-transform": "0.0.1"
+    "vinyl-buffer": "^1.0.1",
+    "vinyl-source-stream": "^2.0.0",
+    "vinyl-transform": "^1.0.0"
   },
   "license": "MIT",
   "main": "index.js",