Add README.md to package.

Author: sharpjs

Directory.Build.props

@@ -24,6 +24,7 @@
     <PackageTags>semantic semver semver2 version versioning git branch msbuild devops teamcity actions</PackageTags>
     <PackageReleaseNotes>$(PackageProjectUrl)/blob/main/CHANGES.md</PackageReleaseNotes>
     <PackageIcon>icon.png</PackageIcon>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
     <RepositoryType>git</RepositoryType>
     <RepositoryUrl>$(PackageProjectUrl).git</RepositoryUrl>
     <MinClientVersion>4.8.0</MinClientVersion>

src/Subatomix.Build.Versioning.Semantic.msbuildproj

@@ -30,7 +30,8 @@
   <ItemGroup>
     <Content Include="*.props" />
     <Content Include="*.targets" />
-    <Content Include="icon.png" PackagePath=""/>
+    <Content Include="icon.png" PackagePath="$(PackageIcon)"/>
+    <Content Include="..\README.md" PackagePath="$(PackageReadmeFile)"/>
   </ItemGroup>
 
   <Import Project="Subatomix.Build.Versioning.Semantic.props" />