Remove jdk8 from PR build (#3082)

Author: RishiRajAnand

.github/workflows/pull_request.yml

@@ -17,7 +17,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        java-version: [8, 11]
+        java-version: [11]
         maven-version: ['3.8.1']
       fail-fast: true
     runs-on: ${{ matrix.os }}