Update .travis.yml

Update .travis.yml

Could not satisfy all requirements for jinja2>=2.9:
    jinja2>=2.9(from: ara), jinja2<2.9(from: ansible==2.2.1.0)

.travis.yml: add netaddr (for the ipaddr Jinja2 filter)

.travis.yml: add ansible-lint pycodestyle yamllint

Update .travis.yml