ci(actions): specify auto-merge using version, use latest version

Author: jrolfs

.github/workflows/automerge.yml

@@ -22,7 +22,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: automerge
-        uses: 'pascalgn/automerge-action@f81beb99aef41bb55ad072857d43073fba833a98'
+        uses: 'pascalgn/automerge-action@v0.14.1'
         env:
           GITHUB_TOKEN: '${{ secrets.AUTOMERGE_TOKEN }}'
           MERGE_LABELS: 'automerge,!work in progress'