chore: Simplify semantic release automation

Author: prantlf

.travis.yml

@@ -10,7 +10,7 @@ node_js:
   - '8'
   - '6'
 after_success:
-  - npm run travis-deploy-once "npm run semantic-release"
+  - npx semantic-release
 branches:
   except:
     - /^v\d+\.\d+\.\d+$/