Optimize GitHub Actions workflow by using PowerShell on Windows runners for better compatibility

Author: tleonhardt

.github/workflows/tests.yml

@@ -16,9 +16,6 @@ jobs:
       fail-fast: false
 
     runs-on: ${{ matrix.os }}
-    defaults:
-      run:
-        shell: bash
     steps:
       - name: Check out
         uses: actions/[email protected]
@@ -34,9 +31,11 @@ jobs:
           allow-prereleases: true
       - name: Install the project
         run: uv sync --all-extras --dev
+        shell: bash
 
       - name: Run tests
         run: uv run python -Xutf8 -m pytest --cov --cov-config=pyproject.toml --cov-report=xml tests
+        shell: bash
 
       - name: Upload test results to Codecov
         if: ${{ !cancelled() }}
@@ -45,6 +44,7 @@ jobs:
           flags: python${{ matrix.python-version }}
           name: codecov-umbrella-test-results
           token: ${{ secrets.CODECOV_TOKEN }}
+        shell: bash
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v5
         with:
@@ -54,3 +54,4 @@ jobs:
           name: codecov-umbrella
           token: ${{ secrets.CODECOV_TOKEN }}
           verbose: true
+        shell: bash