ci: add action for shellcheck linter

we are adding new linter for shellcheck.
As we are writing more shell scripts this
will help maintain quality.

Also, doing all the changes required in
bash files to pass this shellcheck.

Closes: https://github.com/rook/rook/issues/8431
Signed-off-by: subhamkrai <srai@redhat.com>

.github/workflows/shellcheck.yaml

@@ -0,0 +1,28 @@
+name: ShellCheck
+on:
+  push:
+    tags:
+      - v*
+    branches:
+      - master
+      - release-*
+  pull_request:
+    branches:
+      - master
+      - release-*
+
+jobs:
+  shellcheck:
+    name: Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Run ShellCheck
+      uses: ludeeus/action-shellcheck@master
+      with:
+        severity: warning
+        check_together: 'yes'
+        disable_matcher: false
+        additional_files: build/run build/reset build/sed-in-place
+        ignore: olm
+        format: gcc