Python wheels fixes (#251)

- Set README type to Markdown
- Only publish to PyPI for tags

.github/workflows/release.yml

@@ -52,6 +52,7 @@ jobs:
   pypi-publish:
     name: upload release to PyPI
     needs: validate
+    if: github.event.workflow_run.head_branch != 'main'
     runs-on: ubuntu-latest
     environment: release
     permissions:

python/setup.py

@@ -53,6 +53,7 @@ def get_tag(self):
     version=get_version(),
     description="Rewrite of the MLFlow tracking server with a focus on scalability.",
     long_description=get_long_description(),
+    long_description_content_type="text/markdown",
     packages=find_packages(),
     include_package_data=True,
     data_files=get_data_files(),