Pin runs-on image: ubuntu-latest -> ubuntu:22.04

Author: yasulab

.github/workflows/test.yml

@@ -51,9 +51,11 @@ jobs:
   deploy:
     needs: test
     if: github.ref == 'refs/heads/main'
-    runs-on: ubuntu-latest
+    # TODO: This workflows depend on Ubuntu version.
+    # https://github.com/AkhileshNS/heroku-deploy/issues/186
+    runs-on: ubuntu:22.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: akhileshns/heroku-deploy@v3.13.15
         with:
           heroku_api_key:  ${{ secrets.HEROKU_API_KEY }}