message: Fix output base
diff: @@ -131,8 +131,9 @@ def output_base():
  root = pathlib.Path(OUTPUT_ROOT.get(platform.system()))
  agent = os.getenv('BUILDKITE_AGENT_NAME', 'agent')
  pipeline = os.getenv('BUILDKITE_PIPELINE_SLUG', 'pipeline')
  - branch = os.getenv('BUILDKITE_PULL_REQUEST_BASE_BRANCH',
  - os.getenv('BUILDKITE_BRANCH', 'branch'))
  + branch = os.getenv('BUILDKITE_PULL_REQUEST_BASE_BRANCH', '')
  + if branch == '':
  + branch = os.getenv('BUILDKITE_BRANCH', 'branch')
  return root / agent / pipeline / branch
  