CI: switch to actions/checkout@v2 (#36)

Author: XhmikosR

.github/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
 
     steps:
       - name: Clone repository
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
 
       - name: Clone nodejs/node repository
         run: git clone https://github.com/nodejs/node.git tmp --depth 1