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

Author: renovate[bot]

.github/workflows/danger.yml

@@ -10,7 +10,7 @@ jobs:
     name: Review, Lint, Verify
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Danger
         uses: docker://ghcr.io/danger/danger-swift-with-swiftlint:3.15.0

.github/workflows/documentation.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: macos-15
     steps:
       - name: Checkout the repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Ruby
         uses: ruby/setup-ruby@v1

.github/workflows/release.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: macos-15
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Dependencies
         run: make install-ci