Try to fix reference to readme for nuget

Author: Bas Visscher

ESPTool/EspDotNet.csproj

@@ -17,5 +17,6 @@
 	<ItemGroup>
 		<PackageReference Include="System.IO.Ports" Version="5.0.1" />
 		<PackageReference Include="Microsoft.Extensions.Logging" Version="8.0.0" />
+    <None Include="..\README.md" Pack="true" PackagePath="README.md" />
 	</ItemGroup>
 </Project>