Update production deploy to use release branch

Author: catarak

.github/workflows/deploy.yml

@@ -20,6 +20,8 @@ jobs:
     steps:
       - name: Check out the repo
         uses: actions/checkout@v2
+        with:
+          ref: release
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
       - name: Login to Docker Hub