build(project): change travis openjdk to 11.

PhantomThief · PhantomThief · commit d4aed7c4a5e9 · 2022-07-29T20:24:15.000+08:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,5 +1,5 @@
 language: java
 jdk:
-  - openjdk8
+  - openjdk11
 after_success:
   - mvn clean test jacoco:report coveralls:report
