chore(deps): bump actions/setup-java from 4 to 6

Bumps [actions/setup-java](https://github.com/actions/setup-java) from 4 to 6.
- [Release notes](https://github.com/actions/setup-java/releases)
- [Commits](actions/setup-java@v4...v6)

---
updated-dependencies:
- dependency-name: actions/setup-java
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -43,7 +43,7 @@ jobs:
           fetch-depth: 1
 
       - name: Set up JDK ${{ matrix.jdk }}
-        uses: actions/setup-java@v5
+        uses: actions/setup-java@v6
         with:
           distribution: temurin
           java-version: ${{ matrix.jdk }}
@@ -140,7 +140,7 @@ jobs:
       contents: read
     steps:
       - uses: actions/checkout@v7
-      - uses: actions/setup-java@v5
+      - uses: actions/setup-java@v6
         with:
           distribution: temurin
           java-version: "21"

.github/workflows/pitest-nightly.yml

@@ -17,7 +17,7 @@ jobs:
     steps:
       - uses: actions/checkout@v7
 
-      - uses: actions/setup-java@v4
+      - uses: actions/setup-java@v6
         with:
           distribution: temurin
           java-version: "21"

.github/workflows/release.yml

@@ -26,7 +26,7 @@ jobs:
         with:
           fetch-depth: 0
 
-      - uses: actions/setup-java@v5
+      - uses: actions/setup-java@v6
         with:
           distribution: temurin
           java-version: "21"