Attempt to fix pythonpublish on Linux.

.github/workflows/pythonpublish.yml

@@ -4,6 +4,8 @@ on:
   push:
     tags:
       - dulwich-*
+    branches:
+      - master
 
 jobs:
   deploy:
@@ -24,10 +26,18 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install setuptools wheel twine fastimport
-    - name: Build and publish
+    - name: Build
+      run: |
+        python setup.py sdist bdist_wheel
+        mkdir wheelhouse
+        mv dist/*.whl wheelhouse
+      if: "matrix.os != 'ubuntu-latest'"
+    - name: Build and publish (Linux)
+      uses: RalfG/python-wheels-manylinux-build@v0.2.2
+      if: "matrix.os == 'ubuntu-latest'"
+    - name: Publish
       env:
         TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
         TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
       run: |
-        python setup.py sdist bdist_wheel
-        twine upload dist/*
+        echo twine upload wheelhouse/*