Update mybatis 3.5.2-SNAPSHOT on Travis CI

Fixes gh-18

Author: kazuki43zoo

.travis.yml

@@ -11,7 +11,7 @@ script:
   # build using mybatis 3.4.x line
   - ./mvnw clean verify -Dmybatis.version=3.4.6
   # build using mybatis 3.5.x snapshot
-  - ./mvnw clean verify -Dmybatis.version=3.5.1-SNAPSHOT
+  - ./mvnw clean verify -Dmybatis.version=3.5.2-SNAPSHOT
 
 after_success:
   - chmod -R 777 ./travis/after_success.sh