Fix CI: Re-enable running shellcheck even when only docs changed

Signed-off-by: Bernhard Kaindl <bernhard.kaindl@cloud.com>

Author: bernhardkaindl

.github/workflows/shellcheck.yaml

@@ -2,10 +2,6 @@ name: ShellCheck
 
 on:
   pull_request:
-    # When only Hugo docs change, this workflow is not required:
-    paths-ignore:
-      - 'doc/**'
-      - '.github/workflows/hugo.yml'
   merge_group:
 
 concurrency:  # On new push, cancel old workflows from the same PR, branch or tag: