implement https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/ (#3348)

Author: jcollins-g

.github/workflows/test.yaml

@@ -43,7 +43,7 @@ jobs:
     steps:
       - name: Store date
         id: date
-        run: echo "::set-output name=today::$(date +'%Y-%m-%d')"
+        run: echo "name=today::$(date +'%Y-%m-%d')" >> $GITHUB_OUTPUT
         shell: bash
       - name: Cache clean flutter
         uses: actions/cache@69d9d449aced6a2ede0bc19182fadc3a0a42d2b0