docs(ci): fix travis syntax error and disable docs deployment for pul… (#3772)

* docs(ci): fix travis syntax error and disable docs deployment for pull requests

* docs(ci): remove branch check to prevent merge conflicts

Author: niklas-wortmann

.travis.yml

@@ -43,4 +43,4 @@ script:
 after_success:
   - if [ "$FULL_VALIDATE" == "true" ]; then npm run test:cover && npx nyc report --reporter=text-lcov | npx coveralls; fi
   - if [ "$FULL_VALIDATE" == "true" ] && [ "$TRAVIS_PULL_REQUEST" = "false" ] && [ -n "$SAUCE_ACCESS_KEY" ]; then npm run build_spec_browser && grunt --gruntfile spec/support/mocha.sauce.gruntfile.js; fi
-  - if [ "$FULL_VALIDATE" == "true"] && [ "$TRAVIS_BRANCH" == "master" ]; then cd docs_app && chmod 755 scripts/deploy-to-firebase.sh && yarn deploy-production; fi
+  - if [ "$FULL_VALIDATE" == "true" ] && [ "$TRAVIS_BRANCH" == "master" ]; then cd docs_app && chmod 755 scripts/deploy-to-firebase.sh && yarn deploy-production; fi