Update readme.md

Author: ufcpp

readme.md

@@ -34,6 +34,21 @@ namespace Sample
 
 [![NuGet](https://img.shields.io/nuget/v/StringLiteralGenerator?style=flat-square)](https://www.nuget.org/packages/StringLiteralGenerator)
 
+```xml
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net5.0</TargetFramework>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="StringLiteralGenerator" Version="1.0.0" />
+    </ItemGroup>
+
+</Project>
+```
+
 For versions earlier than .NET 5 SDK RC2 you may also need to add a reference to `Microsoft.Net.Compilers.Toolset`.
 So the `csproj` may look like this:
 ```xml