Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/package.yml

@@ -38,7 +38,7 @@ jobs:
             os: windows-11-arm
             experimental: false
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v6
         with:

.github/workflows/release.yml

@@ -26,7 +26,7 @@ jobs:
     permissions:
       id-token: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: astral-sh/setup-uv@v7
       - run: uv build
       - name: Smoke test (wheel)