test: add Node.js 12 and 14 in the build matrix

Node.js 8 is removed, as it is now EOL.

Note: the node_modules folder is cached by default

Author: darrachequesne

.travis.yml

@@ -1,17 +1,15 @@
 language: node_js
 sudo: false
 node_js:
-  - '8'
   - '10'
+  - '12'
+  - '14'
 git:
   depth: 1
 matrix:
   include:
     - node_js: 10
       env: BROWSERS=1
-cache:
-  directories:
-    - node_modules
 env:
   global:
     - secure: >-

package.json

@@ -30,5 +30,8 @@
   "scripts": {
     "test": "make test"
   },
-  "license": "MIT"
+  "license": "MIT",
+  "engines": {
+    "node": ">=10.0.0"
+  }
 }