Travis CI: Drop Java 12 build (Java 13 is now Generally Available).

PascalSchumacher · PascalSchumacher · commit 2539fc97dd8d · 2019-09-20T10:19:47.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -19,7 +19,6 @@ sudo: false
 jdk:
   - openjdk8
   - openjdk11
-  - openjdk12
   - openjdk13
   - openjdk-ea
   - oraclejdk11
