gci: Add -f flag to git fetch

This avoids the warning of clobbering tags when fetching tags

Changelog-None

Author: cdecker

.github/workflows/ci.yaml

@@ -31,7 +31,7 @@ jobs:
         uses: actions/[email protected]
 
       - name: Fetch tags for auto versioning
-        run: git fetch --prune --unshallow --tags
+        run: git fetch --prune --unshallow --tags -f
 
       - name: Set up Python 3.6
         uses: actions/setup-python@v2