actions: add shell check action for sealer

Signed-off-by: Allen Sun <[email protected]>

Author: allencloud

.github/workflows/shellcheck.yml

@@ -0,0 +1,16 @@
+name: Shell Check All Scripts
+
+on:
+  pull_request:
+    branches: "*"
+
+jobs:
+  shellcheck:
+    name: Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Run ShellCheck
+      uses: ludeeus/action-shellcheck@master
+      with:
+        ignore_paths: vendor