update travis config

Author: vhf

.travis.yml

@@ -0,0 +1,18 @@
+before_install:
+  - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.9.2
+  - export PATH=$HOME/.yarn/bin:$PATH
+
+cache:
+  yarn: true
+
+git:
+  depth: 10
+
+language: node_js
+
+node_js:
+  - '8'
+  - '10'
+  - '12'
+  - '14'
+