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

Author: renovate[bot]

.github/workflows/release_gem.yml

@@ -10,7 +10,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: '3.4.8'
@@ -28,7 +28,7 @@ jobs:
       version: ${{ steps.release-gem.outputs.version }}
       increment: ${{ steps.release-gem.outputs.increment }}
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0
     - id: release-gem

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
         ruby_version: ["3.2", "3.3", "3.4"]
         os: ["ubuntu-latest","windows-latest","macos-latest"]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
@@ -47,7 +47,7 @@ jobs:
         ruby_version: ["3.2", "3.3", "3.4"]
         os: ["ubuntu-latest","windows-latest","macos-latest"]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby_version }}