feat: add GitHub Actions workflow to set up and regenerate fixtures on labeled pull requests

Author: ryan-gang

.github/workflows/fixtures-with-setup.yml

@@ -0,0 +1,24 @@
+name: Setup and regenerate fixtures
+
+permissions:
+  contents: write
+  pull-requests: write
+
+on:
+  pull_request:
+    types:
+      - labeled
+
+jobs:
+  setup-and-regenerate-fixtures:
+    if: github.event.label.name == 'regenerate-fixtures'
+    runs-on: ubuntu-latest
+
+    steps:
+        # No setup step needed, yet.
+      - name: Regenerate Fixtures
+        uses: codecrafters-io/tester-utils/.github/actions/fixtures@master
+        with:
+          tester_repo: git-tester
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          fixture_generation_token: ${{ secrets.TESTER_FIXTURE_GENERATION_GITHUB_TOKEN }}