Remove pre-checkin workflow (not needed)

.github/workflows/pre-checkin.yml

@@ -1,30 +0,0 @@
-name: pre-checkin
-
-on:
-  push:
-    paths-ignore:
-      - '**.md'
-  pull_request:
-    paths-ignore:
-      - '**.md'
-
-jobs:
-  pre-checkin:
-    runs-on: ubuntu-latest
-    steps:
-      -
-        name: Checkout
-        uses: actions/checkout@v2.3.2
-      -
-        name: Install
-        run: yarn install
-      -
-        name: Pre-checkin
-        run: yarn run pre-checkin
-      -
-        name: Check for uncommitted changes
-        run: |
-          if [[ `git status --porcelain` ]]; then
-            git status --porcelain
-            echo "::warning::Found changes. Please run 'yarn run pre-checkin' and push"
-          fi