Move shellcheck job from changelog workflow into a dedicated shellcheck workflow

Co-authored-by: dannywillems <6018454+dannywillems@users.noreply.github.com>

Author: Copilot

.github/workflows/changelog.yaml

@@ -28,12 +28,3 @@ jobs:
           .github/scripts/check-changelog-commit.sh
           "${{ github.event.pull_request.base.sha }}"
 
-  shellcheck:
-    name: Shellcheck
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v6
-      - name: Install shellcheck
-        run: sudo apt-get install -y shellcheck
-      - name: Run shellcheck
-        run: make lint-shell

.github/workflows/shellcheck.yml

@@ -0,0 +1,16 @@
+name: Shellcheck
+on: push
+
+permissions:
+  contents: read
+
+jobs:
+  shellcheck:
+    name: Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - name: Install shellcheck
+        run: sudo apt-get install -y shellcheck
+      - name: Run shellcheck
+        run: make lint-shell