Revert "Use dev hassfest."

Seems dev branch cannot be used. Will have to ignore the hassfest failure until the next release.

This reverts commit 1af52089eaf31093f23f19ec7c171c89bd42e571.

.github/workflows/hassfest-validate.yml

@@ -11,4 +11,4 @@ jobs:
     runs-on: "ubuntu-latest"
     steps:
       - uses: "actions/checkout@v2"
-      - uses: home-assistant/actions/hassfest@dev
+      - uses: home-assistant/actions/hassfest@master