chore(build): Improve travis.yml, allow to check PRs

Author: nodkz

.travis.yml

@@ -24,8 +24,8 @@ after_success:
   - 'curl -Lo travis_after_all.py https://git.io/travis_after_all'
   - python travis_after_all.py
   - export $(cat .to_export_back) &> /dev/null
-  - if [[ "$TRAVIS_JOB_NUMBER" == *.1 ]]; then bash <(curl -s https://codecov.io/bash); fi
-  - if [[ "$TRAVIS_JOB_NUMBER" == *.1 ]]; then npm run semantic-release; fi
+  - if [[ "$TRAVIS_JOB_NUMBER" == *.1 && "$TRAVIS_BRANCH" == "master" && "$TRAVIS_PULL_REQUEST" == "false" ]]; then bash <(curl -s https://codecov.io/bash); fi
+  - if [[ "$TRAVIS_JOB_NUMBER" == *.1 && "$TRAVIS_BRANCH" == "master" && "$TRAVIS_PULL_REQUEST" == "false" ]]; then npm run semantic-release; fi
 branches:
-  only:
-    - master
+  except:
+    - /^v\d+\.\d+\.\d+$/