Only publish from main branch to test PyPI

Author: agners

.github/workflows/build.yaml

@@ -123,6 +123,7 @@ jobs:
                   python3 -m twine upload out/controller/python/home_assistant_chip_core-${{ needs.build_prepare.outputs.version }}-cp37-abi3-manylinux_2_31_${{ matrix.arch.name }}.whl --skip-existing
                   python3 -m twine upload out/controller/python/home_assistant_chip_repl-${{ needs.build_prepare.outputs.version }}-py3-none-any.whl --skip-existing
             - name: Upload wheels to Test PyPI
+              if: ${{ github.ref == 'refs/heads/main' }}
               env:
                   TWINE_USERNAME: "__token__"
                   TWINE_PASSWORD: ${{ secrets.TWINE_TOKEN_TESTPYPI }}