chore: use Java 21

Author: ofek29

.github/workflows/ci.yml

@@ -19,18 +19,14 @@ jobs:
   test:
     runs-on: ubuntu-latest
 
-    strategy:
-      matrix:
-        java-version: [21]
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Set up JDK ${{ matrix.java-version }}
+      - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
-          java-version: ${{ matrix.java-version }}
+          java-version: "21"
           distribution: "temurin"
           cache: maven