CI: add fail-fast: false

This will allow all builds to run even if one fails

PR-URL: #601
Credit: @XhmikosR
Close: #601
Reviewed-by: @ruyadorno

Author: XhmikosR

.github/workflows/ci.yml

@@ -5,6 +5,7 @@ on: [push]
 jobs:
   build:
     strategy:
+      fail-fast: false
       matrix:
         node-version: [8.x, 10.x, 12.x]
         os: [ubuntu-latest, windows-latest]