Switch back to the original version of the coverage action.

.github/workflows/ci.yml

@@ -76,26 +76,24 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.12"
-      - name: Download pre-built packages
-        uses: actions/download-artifact@v4
-        with:
-          name: Packages
-          path: dist
-      - run: tar xf dist/*.tar.gz --strip-components=1
-      - name: Download coverage data
-        uses: actions/download-artifact@v4
+          python-version-file: .python-version-default
+      - uses: hynek/setup-cached-uv@v2
+      - run: uv pip install --system --upgrade coverage[toml]
+      - uses: actions/download-artifact@v4
         with:
           pattern: coverage-data-*
           merge-multiple: true
 
-      - name: Combine coverage and fail under 100%
+      - name: Combine coverage & fail if it's <100%.
         run: |
-          python -Im pip install --upgrade "coverage[toml]"
+          uv tool install 'coverage[toml]'
+
           coverage combine
           coverage html --skip-covered --skip-empty
+
           # Report and write to summary.
           coverage report --format=markdown >> $GITHUB_STEP_SUMMARY
+
           # Report again and fail if under 100%.
           coverage report --fail-under=100