Bump gulp to v5 (#81)

Author: arpit-jn

dist/angular-lock.min.js

@@ -19,11 +19,11 @@
   },
   "homepage": "https://github.com/auth0/angular-lock#readme",
   "devDependencies": {
-    "gulp": "^4.0.2",
+    "gulp": "^5.0.1",
     "gulp-concat": "^2.6.1",
     "gulp-inject-version": "^1.0.1",
-    "gulp-ng-annotate": "^2.0.0",
-    "gulp-rename": "^2.0.0",
+    "gulp-ng-annotate": "^2.1.0",
+    "gulp-rename": "^2.1.0",
     "gulp-uglify": "^3.0.2"
   },
   "dependencies": {