fix(travis): only deploy on master branch

Author: StephanGerbeth

.travis.yml

@@ -18,7 +18,6 @@ script:
   - npm run build
 after_success:
   - npm run travis-deploy-once "npm run semantic-release"
-  # - npm install --prefix ./functions
   # - firebase deploy --only functions --token "${FIREBASE_TOKEN}"
 before_deploy:
   - npm install --prefix ./functions