chore: Add master branch for linting on TravisCI

See conventional-changelog/commitlint#7

Author: kumar303

.travis.yml

@@ -4,6 +4,8 @@ node_js:
 - '0.12'
 - '4'
 before_install:
+# Get a master branch for conventional-changelog-lint
+- git remote set-branches origin master && git fetch
 - npm install -g npm
 script: COVERAGE=y npm test && npm run lint-commit-msg
 after_script: npm run publish-coverage