Releasing v2.21.0 (#699)

Author: github-actions[bot]

python/publish/__init__.py

@@ -11,7 +11,7 @@
     UnitTestRunDeltaResults, UnitTestRunResultsOrDeltaResults, ParseError
 
 # keep the version in sync with action.yml and docker/action.yml
-__version__ = 'v2.20.0'
+__version__ = 'v2.21.0'
 
 logger = logging.getLogger('publish')
 digest_prefix = '[test-results]:data:'