ci: revert to checkout@v5

Author: nidotls

.github/workflows/build.yml

@@ -11,7 +11,7 @@ jobs:
       matrix:
         java: [ "17", "21" ] # "25"
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v5
 
       - name: Set up JDK ${{ matrix.java }}
         uses: actions/setup-java@v5

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     if: "!contains(github.event.head_commit.message, '[ci skip]') && !contains(github.event.head_commit.message, '[skip ci]')"
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v5
         with:
           fetch-depth: 0