build: support Node.js 13.x

Author: dougwilson

.github/workflows/ci.yml

@@ -25,6 +25,7 @@ jobs:
         - Node.js 10.x
         - Node.js 11.x
         - Node.js 12.x
+        - Node.js 13.x
 
         include:
         - name: Node.js 0.8
@@ -81,6 +82,9 @@ jobs:
         - name: Node.js 12.x
           node-version: "12.22"
 
+        - name: Node.js 13.x
+          node-version: "13.13"
+
     steps:
     - uses: actions/checkout@v2