Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/actionlint.yml

@@ -9,7 +9,7 @@ jobs:
     name: runner / actionlint
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5.0.1
+      - uses: actions/checkout@v6.0.0
       - name: actionlint
         uses: reviewdog/[email protected]
         with:

.github/workflows/release.yml

@@ -23,7 +23,7 @@ jobs:
     name: release
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5.0.1
+      - uses: actions/checkout@v6.0.0
 
       - if: ${{ matrix.target == 'x86_64-pc-windows-gnu' }}
         run: |

.github/workflows/review.yml

@@ -16,7 +16,7 @@ jobs:
   rust:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5.0.1
+      - uses: actions/checkout@v6.0.0
 
       - uses: actions-rs/[email protected]
         with: