Add dco and release drafter workflows (opensearch-project#217)

Signed-off-by: Joshua Li <joshuali925@gmail.com>

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

@@ -0,0 +1,45 @@
+# The overall template of the release notes
+template: |
+  Compatible with OpenSearch and OpenSearch Dashboards Version $RESOLVED_VERSION
+  $CHANGES
+
+# Setting the formatting and sorting for the release notes body
+name-template: Version $RESOLVED_VERSION
+change-template: "* $TITLE ([#$NUMBER](https://github.com/opensearch-project/dashboards-reports/pull/$NUMBER))"
+sort-by: merged_at
+sort-direction: ascending
+replacers:
+  - search: '##'
+    replace: '###'
+
+# Organizing the tagged PRs into unified categories
+categories:
+  - title: 'Breaking Changes'
+    labels:
+      - 'Breaking Changes'
+  - title: 'Features'
+    labels:
+      - 'feature'
+  - title: 'Enhancements'
+    labels:
+      - 'enhancement'
+  - title: 'Bug Fixes'
+    labels:
+      - 'bug'
+  - title: 'Infrastructure'
+    labels:
+      - 'infra'
+      - 'test'
+      - 'dependencies'
+      - 'github actions'
+  - title: 'Documentation'
+    labels:
+      - 'documentation'
+  - title: 'Maintenance'
+    labels:
+      - "version compatibility"
+      - "maintenance"
+  - title: 'Refactoring'
+    labels:
+      - 'refactor'
+      - 'code quality'

.github/workflows/dco.yml

@@ -0,0 +1,18 @@
+name: Developer Certificate of Origin Check
+
+on: [pull_request]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Get PR Commits
+        id: 'get-pr-commits'
+        uses: tim-actions/get-pr-commits@v1.1.0
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+      - name: DCO Check
+        uses: tim-actions/dco@v1.1.0
+        with:
+          commits: ${{ steps.get-pr-commits.outputs.commits }}

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

@@ -0,0 +1,21 @@
+name: Release Drafter
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  update_release_draft:
+    name: Update draft release notes
+    runs-on: ubuntu-latest
+    steps:
+      # Drafts your next Release notes as Pull Requests are merged into "main"
+      - name: Update draft release notes
+        uses: release-drafter/release-drafter@v5
+        with:
+          config-name: draft-release-notes-config.yml
+          tag: (None)
+          version: 1.2.0.0
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}