Update actions/checkout action to v6 (#20)

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

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -10,7 +10,7 @@ jobs:
     outputs:
       version: ${{ steps.get-version.outputs.version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Setup Java 17
         uses: actions/setup-java@v5
         with:
@@ -68,7 +68,7 @@ jobs:
     env:
       GRADLE_OPTS: "-Dorg.gradle.jvmargs=-Xmx4g -XX:MaxMetaspaceSize=512m"
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Setup Java 17
         uses: actions/setup-java@v5
         with:

.github/workflows/release.yaml

@@ -20,7 +20,7 @@ jobs:
     env:
       GRADLE_OPTS: "-Dorg.gradle.jvmargs=-Xmx4g -XX:MaxMetaspaceSize=512m"
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0