Set the NuGet package copyright text

Author: jeffhandley

Directory.Build.props

@@ -6,6 +6,7 @@
     <Nullable>enable</Nullable>
     <IsPackable>false</IsPackable>
     <PackageVersion>0.1.0-preview</PackageVersion>
+    <Copyright>Copyright (c) Anthropic and Contributors</Copyright>
     <RepoRoot>$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)'))</RepoRoot>
     <VSTestLogger>trx%3bLogFileName=$(MSBuildProjectName).$(TargetFramework).$(OS).trx</VSTestLogger>
     <VSTestResultsDirectory>$(RepoRoot)/artifacts/TestResults</VSTestResultsDirectory>
@@ -15,4 +16,4 @@
   <PropertyGroup Condition="'$(GITHUB_ACTIONS)' == 'true'">
     <ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
   </PropertyGroup>
-</Project>
+</Project>