add shellcheck action (#82)

Author: rickycodes

.github/workflows/shellcheck.yml

@@ -0,0 +1,17 @@
+name: shellcheck
+
+permissions:
+  checks: write
+
+on: [push]
+
+jobs:
+  lint:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+      - name: ShellCheck Action
+        uses: fearphage/shellcheck-action@95d2a3d34d381a7314c286ea1725ca8cce3b51fd
+        env:
+          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}