adding shformat on push and pull

.github/workflows/shellcheck.yml

@@ -0,0 +1,16 @@
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  shellcheck:
+    name: Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Run ShellCheck
+      uses: ludeeus/action-shellcheck@master