Merge pull request #657 from meeseeksmachine/auto-backport-of-pr-653-on-0.11.x

Backport PR #653 on branch 0.11.x (Duplicate prettier configuration)

Author: fcollonval

package.json

@@ -119,9 +119,6 @@
       "git add"
     ]
   },
-  "prettier": {
-    "singleQuote": true
-  },
   "repository": {
     "type": "git",
     "url": "https://github.com/jupyterlab/jupyterlab-git.git"