Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/export-notion-blocks-and-commit.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 35
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v6
         with:

.github/workflows/lint-and-check-types.yml

@@ -6,7 +6,7 @@ jobs:
     name: Lint and Check Types
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v6
         with: