slightly improve robustness of git_helper to malformed tags

Author: strtgbb

tests/ci/git_helper.py

@@ -277,7 +277,7 @@ def _commits_since(self, ref_name):
 
     def _update_tags(self, suppress_stderr: bool = False) -> None:
         stderr = subprocess.DEVNULL if suppress_stderr else None
-        self.latest_tag = self.run("git describe --tags --abbrev=0", stderr=stderr)
+        self.latest_tag = self.run("git describe --tags --abbrev=0 --match='v*'", stderr=stderr)
         self.commits_since_latest = self._commits_since(self.latest_tag)
 
         self.latest_upstream_tag = self.run("git describe --tags --abbrev=0 --match='*-*'", stderr=stderr)