[Actions] Use GitHub actions to automatically generate release notes (#683)

Context: https://github.com/xamarin/java.interop/wiki/Release-Notes
Context: https://www.nuget.org/packages/noted
Context: https://github.com/jpobst/noted

Create a GitHub action that automatically generates draft release notes
from merged PR's that contain the label `release-notes`.

These release notes are placed on the wiki, along with instructions on
how to include a PR and how to format the release note message.

This action runs every morning at 06:00 UTC.  Once this workflow is
committed to `master`, it should also be available to be run manually
via the Actions tab:

	https://github.blog/changelog/2020-07-06-github-actions-manual-triggers-with-workflow_dispatch/.

Author: jpobst

.github/workflows/release-notes.yml

@@ -0,0 +1,47 @@
+# This action runs every day and updates the draft release notes on the wiki
+# from comments put on PR's tagged with the `release-notes` label.
+name: Update Release Notes
+
+# Runs every day at 06:00 UTC
+on:
+  schedule:
+    - cron: 0 6 * * *
+  workflow_dispatch:
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Check out wiki repo
+      uses: actions/checkout@v2
+      with: 
+        repository: xamarin/java.interop.wiki
+        path: wiki
+        
+    - name: Setup .NET Core
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: 3.1.x
+        
+    - name: Install Noted
+      run: dotnet tool install -g noted
+      
+    - name: Run Noted
+      run: >
+        noted
+        --repository-owner xamarin 
+        --repository java.interop 
+        --output-directory ${{ github.workspace }}/wiki
+        --repository-name Java.Interop 
+        --token ${{ github.token }}
+         
+    - name: Commit release notes changes
+      working-directory: ${{ github.workspace }}/wiki
+      run: |
+        git config user.email "[email protected]"
+        git config user.name "Release Notes Bot"
+        git add -A
+        git commit -m "Update release notes" || echo "No changes to commit"
+        git push origin master || echo "No changes to commit"