updated rfc-action to 0.1.0 (inform on closed referendas) (#80)

This includes https://github.com/paritytech/rfc-action/pull/34 which
takes into consideration successful RFCs.

When a RFC closed after the last run, it will comment on the open PR (if
it is still open) that the RFC has been closed and how to trigger the
bot to merge the PR.

If it is succesfull, we can automate it to simply close the PRs without
human input.

Also, updated actions/create-github-app-token to latest (version
`1.8.1`)

.github/workflows/rfc-action.yml

@@ -15,10 +15,10 @@ jobs:
     steps:
       - name: Generate a token
         id: generate_token
-        uses: actions/create-github-app-token@v1
+        uses: actions/create-github-app-token@v1.8.1
         with:
-          app_id: ${{ secrets.RFC_BOT_APP_ID }}
-          private_key: ${{ secrets.RFC_BOT_PRIVATE_KEY }}
-      - uses: paritytech/rfc-action@c673cf6776a2f266c7d8cbb29bc2159bea2cdd78 # v0.0.6
+          app-id: ${{ secrets.RFC_BOT_APP_ID }}
+          private-key: ${{ secrets.RFC_BOT_PRIVATE_KEY }}
+      - uses: paritytech/rfc-action@4b7d2a911220b32f2222e083fd32aa62f17739c4 # v0.1.0
         env:
           GH_TOKEN: ${{ steps.generate_token.outputs.token }}