chore(deps): update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/build.yml

@@ -11,7 +11,7 @@ jobs:
     concurrency:
       group: ${{ github.workflow }}-${{ github.ref }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: "3.14"

.github/workflows/deploy.yml

@@ -14,7 +14,7 @@ jobs:
       group: ${{ github.workflow }}-${{ github.ref }}
     steps:
       - name: Clone repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Python environment
         uses: actions/setup-python@v6