use correct JDK

.github/workflows/build.yml

@@ -217,6 +217,9 @@ jobs:
     needs: [buildkit, jlink]
     steps:
       - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: ${{ env.JAVA_VERSION }}
       - name: Set version
         id: setversion
         run: |