chore(ci): Add fixup commit message check

Author: agateau-gg

.github/workflows/test-lint.yml

@@ -16,6 +16,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
       - name: Set up Python 3.9
         uses: actions/setup-python@v1
         with:
@@ -40,6 +43,16 @@ jobs:
         env:
           GITGUARDIAN_API_KEY: ${{ secrets.GITGUARDIAN_API_KEY }}
 
+      - name: Check commit messages
+        if: github.event_name == 'pull_request'
+        run: |
+          if git log --format=%s "origin/$GITHUB_BASE_REF..origin/$GITHUB_HEAD_REF" | grep '^fixup!' ; then
+              echo 'Error: this pull request contains fixup commits. Squash them.'
+              exit 1
+          fi
+          # In case `git log` fails
+          exit "${PIPESTATUS[0]}"
+
   build:
     runs-on: ${{ matrix.os }}
     strategy: