update tested java versions

Signed-off-by: Raymond Augé <rotty3000@apache.org>
diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 0ea546b..99aeb81 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -27,7 +27,7 @@
   JDKxx_Matrix:
     strategy:
       matrix:
-        java: [ 8, 11, 16, 17-ea ]
+        java: [ 8, 11, 17, 18-ea ]
         os: [ ubuntu-latest ]
         include:
         - os: windows-latest