build: move to npm from yarn

Author: keplersj

.travis.yml

@@ -1,34 +1,19 @@
 language: node_js
 
-env:
-  global:
-   - FORCE_COLOR=1
-
 node_js:
   - "node"
   - "lts/*"
 
-install:
-  - yarn
-
-cache:
-  directories:
-    - "node_modules"
-    - ~/.npm
-
-notifications:
-  email: false
-  
 jobs:
   include:
     - stage: test
       script:
-        - yarn test
+        - npm test
       after_success:
         - bash <(curl -s https://codecov.io/bash)
     - stage: release
       script:
-        - npm run release
+        - npx semantic-release
       after_sucess: skip
 
 stages:
@@ -38,4 +23,4 @@ stages:
 
 branches:
   except:
-    - /^v\d+\.\d+\.\d+$/
+    - /^v\d+\.\d+\.\d+$/