Update unit testing workflow to use Zulu distribution for JDK 9 setup

Author: harshithad0703

.github/workflows/unit-testing.yml

@@ -18,10 +18,10 @@ jobs:
       - name: Checkout Repository
         uses: actions/checkout@v4
 
-      - name: Set up JDK 9
+      - name: Set up JDK 9 (Zulu)
         uses: actions/setup-java@v4
         with:
-          distribution: 'temurin'
+          distribution: 'zulu'
           java-version: '9'
           cache: maven