Don't bump version of tagged release

Author: Bouke

.github/workflows/publish.yml

@@ -15,19 +15,21 @@ jobs:
       - uses: actions/checkout@v2
         with:
           fetch-depth: 0
-      - name: Determine package version
-        id: vars
-        run: |
-          [[ ! $GITHUB_REF == refs/tags/* ]] && echo ::set-output name=version::$(git describe --tags | sed -r 's/-(.*?)-(.*?)$/.dev\1/g') || true
-          [[ $GITHUB_REF == refs/tags/* ]] && echo ::set-output name=version::${GITHUB_REF#refs/*/} || true
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v2
         with:
           python-version: 3.8
       - name: Install build packages
         run: pip install wheel bumpversion
+      - name: Determine package version
+        id: vars
+        run: |
+          [[ ! $GITHUB_REF == refs/tags/* ]] && echo ::set-output name=version::$(git describe --tags | sed -r 's/-(.*?)-(.*?)$/.dev\1/g') || true
+          [[ $GITHUB_REF == refs/tags/* ]] && echo ::set-output name=version::${GITHUB_REF#refs/*/} || true
+        if: ${{ !startsWith(github.ref, 'refs/tags') }}
       - name: Bump version number
         run: bumpversion patch --new-version ${{ steps.vars.outputs.version }} --no-tag --no-commit --verbose
+        if: ${{ !startsWith(github.ref, 'refs/tags') }}
       - name: 🐍 Build package
         run: python setup.py sdist bdist_wheel
       - name: 📦 Publish package to TestPyPI