Remove unnecessary dependency

It's built-in the SDK nowadays

Author: kzu

src/WebSocketPipe/WebSocketPipe.csproj

@@ -9,7 +9,6 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="all" />
     <PackageReference Include="System.IO.Pipelines" Version="6.0.3" />
   </ItemGroup>