Support openjdk13 and ea on Travis CI

Fixes gh-67

Author: kazuki43zoo

.travis.yml

@@ -1,6 +1,8 @@
 language: java
 
 jdk:
+  - openjdk-ea
+  - openjdk13
   - openjdk12
   - openjdk11
   - openjdk8

pom.xml

@@ -77,6 +77,9 @@
   <properties>
     <clirr.comparisonVersion>1.1.2</clirr.comparisonVersion>
     <module.name>org.mybatis.scripting.freemarker</module.name>
+
+    <!-- Remove after parent 32 (support for jdk 13) -->
+    <jacoco.version>0.8.4</jacoco.version>
   </properties>
 
   <dependencies>