ci(travis): try to fix gh-pages for pull requests

Author: aronhelser

.travis.yml

@@ -18,7 +18,7 @@ script:
   - git config --global user.name "Travis CI"
   - git config --global user.email "[email protected]"
   - export GIT_PUBLISH_URL=https://${GH_TOKEN}@github.com/wwayne/react-tooltip.git
-  - if [ "$TRAVIS_BRANCH" == "master" ]; then npm run gh-pages -- --repo ${GIT_PUBLISH_URL}; fi
+  - if [ "$TRAVIS_BRANCH" == "master" ] && [ "$TRAVIS_PULL_REQUEST" = "false" ]; then npm run gh-pages -- --repo ${GIT_PUBLISH_URL}; fi
 
 after_success:
   - npm run semantic-release