Merge pull request #789 from owncloud/revert-784-dependabot/npm_and_yarn/gulp-5.0.0

Revert "chore(deps-dev): bump gulp from 4.0.2 to 5.0.0"

Author: mmattel

package.json

@@ -59,7 +59,7 @@
     "eslint-plugin-n": "^16.6.2",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-promise": "^6.1.1",
-    "gulp": "^5.0.0",
+    "gulp": "^4.0.2",
     "gulp-concat": "^2.6.1",
     "gulp-connect": "^5.2.0",
     "gulp-eslint": "^6.0.0",