ci: move PR body check to a different workflow

Move PR body check to a workflow that monitors editing of PRs.
Avoids rerunnin compliance check and other heavy weights workflows on
just an edit of the PR body.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

.github/workflows/compliance.yml

@@ -65,14 +65,6 @@ jobs:
         west config manifest.group-filter -- +ci,-optional
         west update -o=--depth=1 -n 2>&1 1> west.update.log || west update -o=--depth=1 -n 2>&1 1> west.update2.log
 
-    - name: Check for PR description
-      if: ${{ github.event.pull_request.body == '' }}
-      continue-on-error: true
-      id: pr_description
-      run: |
-        echo "Pull request description cannot be empty."
-        exit 1
-
     - name: Run Compliance Tests
       continue-on-error: true
       id: compliance

.github/workflows/do_not_merge.yml

@@ -1,8 +1,14 @@
-name: Do Not Merge
+name: PR Metadata Check
 
 on:
   pull_request:
-    types: [synchronize, opened, reopened, labeled, unlabeled]
+    types:
+      - synchronize
+      - opened
+      - reopened
+      - labeled
+      - unlabeled
+      - edited
 
 permissions:
   contents: read
@@ -22,3 +28,13 @@ jobs:
           echo "Pull request is labeled as 'DNM', 'TSC', 'Architecture Review' or 'dev-review'."
           echo "This workflow fails so that the pull request cannot be merged."
           exit 1
+
+  empty_pr_description:
+    if: ${{ github.event.pull_request.body == '' }}
+    name: PR Description
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Check for PR description
+        run: |
+          echo "Pull request description cannot be empty."
+          exit 1