Shellcheck the scripts

Author: vmcj

.github/workflows/shellcheck.yml

@@ -0,0 +1,18 @@
+name: 'Shellcheck'
+
+on:
+  push:
+    branches:
+      - main
+  pull_request_target:
+    branches:
+      - main
+
+jobs:
+  shellcheck:
+    name: Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Run ShellCheck
+        uses: ludeeus/action-shellcheck@master