chore: update GitHub Actions to latest major versions (#879)

- actions/checkout v5 -> v7
- actions/setup-python v6 -> v7
- actions/configure-pages v5 -> v6
- actions/upload-pages-artifact v3 -> v5
- actions/deploy-pages v4 -> v5
- actions/upload-artifact v4 -> v7
- actions/download-artifact v4 -> v8
- docker/setup-qemu-action v3 -> v4
- docker/setup-buildx-action v3 -> v4
- docker/metadata-action v5 -> v6
- docker/login-action v3 -> v4
- docker/build-push-action v6 -> v7
- codecov/codecov-action v5 -> v7
- peter-evans/create-pull-request v7 -> v8

codecov/test-results-action (already replaced by codecov-action with
report_type: test_results) and pypa/gh-action-pypi-publish@release/v1
(moving branch, still the current major) need no change.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/python-tests.yml

@@ -15,9 +15,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v7
     - name: Set up Python
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@v7
       with:
         python-version: "3.13"
     - name: Install Python dependencies
@@ -65,9 +65,9 @@ jobs:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v7
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@v7
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install system dependencies
@@ -90,7 +90,7 @@ jobs:
       run: |
         hatch build
     - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v5
+      uses: codecov/codecov-action@v7
       with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: false
@@ -101,7 +101,7 @@ jobs:
       # codecov/test-results-action is deprecated in favor of running
       # codecov-action a second time with report_type: test_results.
       if: ${{ !cancelled() }}
-      uses: codecov/codecov-action@v5
+      uses: codecov/codecov-action@v7
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         report_type: test_results