upload to testpypi by default to make sure the action works

Author: masklinn

.github/workflows/release-wheels.yml

@@ -255,8 +255,9 @@ jobs:
         with:
           subject-path: 'dist/*'
       - name: Publish to PyPI
-        if: github.event_name == 'workflow_dispatch' && inputs.release
         uses: PyO3/maturin-action@04ac600d27cdf7a9a280dadf7147097c42b757ad  # 1.50.1
         with:
           command: upload
           args: --non-interactive --skip-existing dist/*
+        env:
+          MATURIN_REPOSITORY: ${{ (github.event_name == 'workflow_dispatch' && inputs.release) && 'pypi' || 'testpypi' }}