CI: ALlow coveralls to fail and tests to still pass

We are seeing problems where coveralls is failing to send and
the whole tests is marked as failed, even if all the pytest etc passed.

This is holding up development and releases and coveralls isn't important enought for that.

.github/workflows/test.yml

@@ -26,4 +26,4 @@ jobs:
       run: py.test -m "geo" --cov --cov-append .
     - env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      run: coveralls --service=github
+      run: coveralls --service=github || true