Add release draft workflow (opendistro-for-elasticsearch#35)

Add draft config and workflow file.

Author: VijayanB

.github/draft-release-notes-config.yml

@@ -0,0 +1,39 @@
+# The overall template of the release notes
+template: |
+  $CHANGES
+
+# Setting the formatting and sorting for the release notes body
+name-template: Version (set version here)
+change-template: '* $TITLE (#$NUMBER)'
+sort-by: merged_at
+sort-direction: ascending
+replacers:
+  - search: '##'
+    replace: '###'
+
+# Organizing the tagged PRs into categories
+categories:
+  - title: 'Breaking Changes'
+    labels:
+      - 'Breaking Changes'
+  - title: 'Features'
+    labels:
+      - 'Features'
+  - title: 'Enhancements'
+    labels:
+      - 'Enhancements'
+  - title: 'Bug Fixes'
+    labels:
+      - 'Bug Fixes'
+  - title: 'Infrastructure'
+    labels:
+      - 'Infrastructure'
+  - title: 'Documentation'
+    labels:
+      - 'Documentation'
+  - title: 'Maintenance'
+    labels:
+      - 'Maintenance'
+  - title: 'Refactoring'
+    labels:
+      - 'Refactoring'

.github/workflows/draft-release-notes-workflow.yml

@@ -0,0 +1,20 @@
+name: Release Drafter
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  update_release_draft:
+    name: Update draft release notes
+    runs-on: ubuntu-latest
+    steps:
+      - name: Update draft release notes
+        uses: release-drafter/release-drafter@v5
+        with:
+          config-name: draft-release-notes-config.yml
+          name: Version (set here)
+          tag: (None)
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}