chore: readd readme

Author: IvanJosipovic

src/Function.SDK.CSharp.SourceGenerator/Function.SDK.CSharp.SourceGenerator.csproj

@@ -29,6 +29,10 @@
     <PackageReference Include="YamlDotNet.System.Text.Json" Version="1.6.6" PrivateAssets="all"  />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Include="..\..\README.md" Pack="true" PackagePath="\" />
+  </ItemGroup>
+
   <ItemGroup>
     <!-- Generator dependencies -->
     <None Include="$(OutputPath)\$(AssemblyName).dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />