Update actions/checkout action to v6 (#66)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/build-website.yml

@@ -19,7 +19,7 @@ jobs:
     name: Build website
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 1
       - name: Set up JDK ${{ env.JDK_VERSION }}

.github/workflows/run-dev-build.yml

@@ -14,7 +14,7 @@ jobs:
         os: [ubuntu-latest] # [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up JDK ${{ matrix.java_version }}
         uses: actions/setup-java@v4
         with:

.github/workflows/run-release-build.yml

@@ -13,7 +13,7 @@ jobs:
         os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: main
       - name: Set up JDK ${{ matrix.java_version }}