fix: workflow files

Author: santoshyadavdev

.github/workflows/main.yml

@@ -10,7 +10,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: 12.x
+        node-version: [12.x]
 
     steps:
       - uses: actions/checkout@v1

.github/workflows/nodejs.yml

@@ -11,7 +11,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: 12.x
+        node-version: [12.x]
 
     steps:
       - uses: actions/checkout@v1