fix: use JDK 21 in CodeQL workflow to match parent 15.7.0 release target

Author: marevol

.github/workflows/codeql-analysis.yml

@@ -60,10 +60,10 @@ jobs:
         key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
         restore-keys: |
           ${{ runner.os }}-maven-
-    - name: Set up JDK 17
+    - name: Set up JDK 21
       uses: actions/setup-java@v4
       with:
-        java-version: '17'
+        java-version: '21'
         distribution: 'temurin'
     - name: Checkout fess-parent
       uses: actions/checkout@v4