Update CI to generate release notes

Author: natemcmaster

.github/workflows/ci.yml

@@ -86,7 +86,8 @@ jobs:
         with:
           name: ${{ env.PACKAGE_VERSION }}
           tag_name: v${{ env.PACKAGE_VERSION }}
-          body: |
+          generate_release_notes: true
+          append_body: |
             ### How to get this update
 
             Packages have been posted to these feeds:

Directory.Build.props

@@ -42,6 +42,10 @@
     <SourceRevisionId Condition="'$(SourceRevisionId)' == ''">$(BUILD_SOURCEVERSION)</SourceRevisionId>
     <PackageVersion>$(VersionPrefix)</PackageVersion>
     <PackageVersion Condition="'$(IncludePreReleaseLabelInPackageVersion)' == 'true'">$(PackageVersion)-$(VersionSuffix)</PackageVersion>
+
+    <PackageReleaseNotes>
+      See release notes at https://github.com/natemcmaster/LettuceEncrypt/releases/tag/v$(PackageVersion).
+    </PackageReleaseNotes>
   </PropertyGroup>
 
   <PropertyGroup>