update travis configuration concerning build jdks

Author: chewiebug

.travis.yml

@@ -5,10 +5,13 @@ language: java
 sudo: false
 
 jdk:
-  - oraclejdk8
   - oraclejdk11
+  - oraclejdk12
+  - oraclejdk13
   - openjdk8
   - openjdk11
+  - openjdk12
+  - openjdk13
 
 # enable cache to stop downloading all maven plugins every time
 cache:
@@ -21,7 +24,7 @@ before_install:
   - pip install --user codecov
 
 # No need to run mvn install, so skip this step
-install: true
+install: skip
 
 # emulate a display for the gui tests
 before_script:

pom.xml

@@ -187,7 +187,7 @@
         <jdk.source.version>1.8</jdk.source.version>
         <jdk.target.version>1.8</jdk.target.version>
         <tools.maven.plugin.version>1.4</tools.maven.plugin.version>
-        <jacoco.maven.plugin.version>0.8.2</jacoco.maven.plugin.version>
+        <jacoco.maven.plugin.version>0.8.4</jacoco.maven.plugin.version>
         <maven.source.plugin.version>3.0.1</maven.source.plugin.version>
         <maven.javadoc.plugin.version>3.0.1</maven.javadoc.plugin.version>
         <maven.gpg.plugin.version>1.6</maven.gpg.plugin.version>