.travis.yml in mihari-0.12.0 vs .travis.yml in mihari-0.13.0

@@ -1,7 +1,7 @@
 ---
 sudo: false
 language: ruby
 cache: bundler
 rvm:
-  - 2.6.1
+  - 2.6
 before_install: gem install bundler -v 2.0.1