Update dependency gulp-load-plugins to v2

Author: renovate-bot

tasks/package.json

@@ -51,7 +51,7 @@
     "gulp-env": "0.4.0",
     "gulp-eslint": "5.0.0",
     "gulp-header": "2.0.7",
-    "gulp-load-plugins": "1.5.0",
+    "gulp-load-plugins": "2.0.4",
     "gulp-mocha": "6.0.0",
     "gulp-plumber": "1.2.1",
     "gulp-rename": "1.4.0",