Push to GCR build broken

- update to Java 11

For #182

Author: srl295

.github/workflows/push-jsp-on-tag.yml

@@ -8,10 +8,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - name: Set up JDK 1.8
+    - name: Set up JDK 11
       uses: actions/setup-java@v1
       with:
-        java-version: 1.8
+        java-version: 11
     - name: Cache local Maven repository
       uses: actions/cache@v2
       with: