fix: update trigger condition of ci workflow

Author: matheusdc

.github/workflows/ci.yml

@@ -1,9 +1,6 @@
 name: CI
 
-on:
-  push:
-    branches:
-      - master
+on: [pull_request]
 
 jobs:
   CI:
@@ -20,7 +17,7 @@ jobs:
       - name: Use Node.js (.nvmrc)
         uses: actions/setup-node@v2
         with:
-          node-version: "${{ steps.nvm.outputs.NVMRC }}"
+          node-version: '${{ steps.nvm.outputs.NVMRC }}'
 
       - name: Use cached node_modules
         uses: actions/cache@v1