Merge pull request #2498 from harawata/jdk-18-ga

[ci] Java 18 is now GA

Author: harawata

.github/workflows/ci.yaml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macOS-latest, windows-latest]
-        java: [8, 11, 17, 18-ea, 19-ea]
+        java: [8, 11, 17, 18, 19-ea]
         distribution: ['zulu']
       fail-fast: false
       max-parallel: 4