ci / coveralls: exclude broken version of package

https://github.com/fphammerle/ical2vdir/runs/446819375

.github/workflows/python.yml

@@ -43,7 +43,8 @@ jobs:
     # >=1.9.0 to detect branch name
     # https://github.com/coveralls-clients/coveralls-python/pull/207
     # https://github.com/coverallsapp/github-action/issues/4#issuecomment-547036866
-    - run: pip install 'coveralls>=1.9.0,<2'
+    # 1.11.0 https://github.com/coveralls-clients/coveralls-python/issues/219
+    - run: pip install 'coveralls>=1.9.0,<2,!=1.11.0'
     # https://github.com/coverallsapp/github-action/issues/30
     # https://github.com/coverallsapp/github-action/issues/4#issuecomment-529399410
     - run: coveralls