Add Ansible and Molecule versions to Travis (#217)

Always pulling the latest version may lead to some issues. Versions should only be updated after successfully testing the latest release.

Author: alessfg

.travis.yml

@@ -22,7 +22,8 @@ env:
 before_install:
   - sudo apt-get -qq update
 install:
-  - pip install molecule[docker]
+  - pip install ansible==2.9.2
+  - pip install molecule[docker]==2.22
 script:
   - travis_wait 50 molecule test -s $scenario
 notifications: