Force push on deploy so that we don't have problems with modifying branch history

Author: jfdoming

.github/actions/heroku-deploy/action.yml

@@ -66,5 +66,5 @@ runs:
           config PREVIEW_DEPLOY true
         shell: bash
       - name: Push to Heroku
-        run: git subtree push --prefix backend heroku main
+        run: git push heroku `git subtree split --prefix backend release`:main --force
         shell: bash