Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/actions.yml

@@ -12,7 +12,7 @@ jobs:
     name: Build on Linux & Deploy
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-java@v5
         with:
           distribution: 'temurin'
@@ -64,7 +64,7 @@ jobs:
     name: Test on Windows
     runs-on: windows-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-java@v5
         with:
           distribution: 'temurin'