Update Ubuntu, JDKs used by CI

Author: cowtowncoder

.github/workflows/main.yml

@@ -14,13 +14,12 @@ permissions:
 
 jobs:
   build:
-    runs-on: ${{ matrix.os }}
+    runs-on: 'ubuntu-latest'
     strategy:
       fail-fast: false
       matrix:
         # 01-May-2022, tatu: Until we require Java 8, cannot test against JDK 17 or above
-        java_version: ['8', '11']
-        os: ['ubuntu-20.04']
+        java_version: ['8', '11', '17']
     env:
       JAVA_OPTS: "-XX:+TieredCompilation -XX:TieredStopAtLevel=1"
     steps: