Update ci.yml: always set up JDK 17

Author: cushon

.github/workflows/ci.yml

@@ -58,6 +58,12 @@ jobs:
           java-version: 11
           distribution: 'zulu'
           cache: 'maven'
+      - name: 'Set up JDK 17'
+        uses: actions/setup-java@v4
+        with:
+          java-version: 17
+          distribution: 'zulu'
+          cache: 'maven'
       - name: 'Set up JDK 24 from jdk.java.net'
         uses: oracle-actions/setup-java@v1
         with: