add adopt-openj9 build (#142)

Signed-off-by: Olivier Lamy <olamy@apache.org>

Author: olamy

.github/workflows/maven.yml

@@ -26,7 +26,7 @@ jobs:
       matrix:
         os: [ubuntu-latest,windows-latest, macOS-latest]
         java: [8, 11, 14, 15, 16, 17-ea]
-        jdk: [adopt, zulu]
+        jdk: [adopt-hotspot, zulu, adopt-openj9]
       fail-fast: false
 
     runs-on: ${{ matrix.os }}