Fix release-drafter for 3.x branch (#319)

- Upgrade to release-drafter v7 (v6 _extends directive no longer works)
- Inline org-level config with correct label syntax for v7
- Trigger on plexus-utils-3.x branch instead of master
- Add filter-by-commitish to scope drafts to 3.x releases only

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: gnodet

.github/release-drafter.yml

@@ -1,2 +1,62 @@
-_extends: .github
-tag-template: plexus-utils-$NEXT_MINOR_VERSION
+name-template: $NEXT_PATCH_VERSION
+tag-template: plexus-utils-$NEXT_PATCH_VERSION
+version-template: $MAJOR.$MINOR.$PATCH
+
+categories:
+  - title: ":boom: Breaking changes"
+    labels:
+      - breaking
+  - title: 🚨 Removed
+    label: removed
+  - title: ":tada: Major features and improvements"
+    labels:
+      - major-enhancement
+      - major-rfe
+  - title: 🐛 Major bug fixes
+    labels:
+      - major-bug
+  - title: ⚠️ Deprecated
+    label: deprecated
+  - title: 🚀 New features and improvements
+    labels:
+      - enhancement
+      - feature
+      - rfe
+  - title: 🐛 Bug Fixes
+    labels:
+      - bug
+      - fix
+      - bugfix
+      - regression
+  - title: ":construction_worker: Changes for plugin developers"
+    labels:
+      - developer
+  - title: 📝 Documentation updates
+    label: documentation
+  - title: 👻 Maintenance
+    labels:
+      - chore
+      - internal
+      - maintenance
+  - title: 🔧 Build
+    label: build
+  - title: 🚦 Tests
+    labels:
+      - test
+      - tests
+  - title: 📦 Dependency updates
+    labels:
+      - dependencies
+      - dependency
+      - dependency-upgrade
+exclude-labels:
+  - reverted
+  - no-changelog
+  - skip-changelog
+  - invalid
+
+change-template: '- $TITLE ([#$NUMBER]($URL)) @$AUTHOR'
+
+template: |
+  <!-- Optional: add a release summary here -->
+  $CHANGES

.github/workflows/release-drafter.yml

@@ -2,11 +2,14 @@ name: Release Drafter
 on:
   push:
     branches:
-      - master
+      - plexus-utils-3.x
 jobs:
   update_release_draft:
     runs-on: ubuntu-latest
     steps:
-      - uses: release-drafter/release-drafter@v6
+      - uses: release-drafter/release-drafter@v7
+        with:
+          commitish: plexus-utils-3.x
+          filter-by-commitish: true
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}