Automate release notes generation

.github/actions/draft-release/.eslintrc

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+{
+  "root": true,
+  "extends": [
+    "airbnb",
+    "prettier"
+  ],
+  "env": {
+    "es6": true,
+    "node": true
+  },
+  "rules": {
+    "prettier/prettier": [
+      "error",
+      {
+        "singleQuote": true,
+        "printWidth": 120
+      }
+    ]
+  },
+  "plugins": [
+    "prettier"
+  ]
+}

.github/actions/draft-release/.gitattributes

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+# Mark generated files so diffs are hidden by default.
+dist/index.js linguist-generated=true

.github/actions/draft-release/README.md

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+# Draft release action
+
+This action drafts a release for the specified milestone and release branch.
+
+## Inputs
+
+### `milestone`
+
+**Required** Milestone name.
+
+## Outputs
+
+### `asset_upload_url`
+
+The URL for uploading assets to the release.
+
+## Example usage
+
+```yaml
+uses: ./.github/actions/draft-release
+env:
+  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+with:
+  milestone: v3.2.1
+```

.github/actions/draft-release/action.yml

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+name: 'Draft release'
+description: 'Drafts a release based on the specified milestone'
+inputs:
+  milestone:
+    description: 'Milestone name'
+    required: true
+  release_branch:
+    description: 'Release branch name'
+    required: true
+outputs:
+  asset_upload_url:
+    description: 'The URL for uploading assets to the release'
+runs:
+  using: 'node12'
+  main: 'dist/index.js'