Add Superior ShellCheck Action

Author: one-and-only

.github/workflows/shellcheck.yml

@@ -0,0 +1,15 @@
+name: 'ShellCheck'
+on:
+  - pull_request
+jobs:
+  sh-checker:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - name: Run the sh-checker
+        uses: luizm/action-sh-checker@v0.1.4
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SHELLCHECK_OPTS: -e SC2164 SC2162 # It is posible to exclude some shellcheck warnings.
+        with:
+          sh_checker_comment: true