add shellcheck action to catch script errors

.github/workflows/test-shellcheck.yml

@@ -0,0 +1,19 @@
+name: "Test Shellcheck"
+
+on:
+  workflow_dispatch:
+  push:
+    branches: ["dev"]
+  pull_request:
+    branches: ["dev"]
+
+jobs:
+  shellcheck:
+    name: Run Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Run ShellCheck
+        uses: ludeeus/action-shellcheck@master
+        with:
+          severity: error