Revert "run on node instead of docker"

This reverts commit d40b37db

.github/workflows/push.yml

@@ -20,7 +20,7 @@ jobs:
       - name: "Setup Node.js"
         uses: "actions/setup-node@v1"
         with:
-          node-version: 12
+          node-version: 8.10.0
       - name: "Automated Version Bump"
         uses: "phips28/gh-action-bump-version@master"
         env:

action.yml

@@ -1,8 +1,8 @@
 name: Automated Version Bump
 description: Automated version bump for npm packages.
 runs:
-  using: 'node12'
-  main: 'index.js'
+  using: docker
+  image: Dockerfile
 branding:
   icon: chevron-up
   color: blue