chore: update build matrix

Author: Tobiah

.travis.yml

@@ -2,33 +2,36 @@ language: node_js
 
 os: linux
 
-cache:
-  directories:
-    - ~/.npm
+cache: npm
 notifications:
     email: false
 
 node_js:
-  - "node"
-  - "lts/*"
+  - 'node'
+  - 'lts/*'
+  - 13
+  - 12
+  - 11
+  - 10
+  - 9
+  - 8
 
 stages:
-  - name: lint
-  - name: coverage
+  - lint
+  - test
+  - coverage
   - name: release
     if: branch = master && type NOT IN (pull_request)
   - name: docs
     if: branch = master && type NOT IN (pull_request)
 
 jobs:
   include:
-    - stage: lint
+    - name: lint
       script: npm run lint
-    - stage: test
-      script: npm test
-    - stage: coverage
+    - name: coverage
       script: npm run coverage
-    - stage: release
+    - name: release
       node_js: node
       deploy:
         provider: script