Remove current implementation of SponsorLink for now

Now that SponsorLink is OSS and based on received feedback
it will change in many ways moving forward, we'll for now
remove the current implementation from the package to address
the issues that were raised.

See https://github.com/devlooped/SponsorLink

Author: kzu

src/PackageReferenceCleaner/PackageReferenceCleaner.csproj

@@ -13,15 +13,20 @@
     <PackageReadmeFile>readme.md</PackageReadmeFile>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Compile Remove="SponsorLinker.cs" />
+  </ItemGroup>
+
   <ItemGroup>
     <None Include="..\..\readme.md" Link="readme.md" />
+    <None Include="SponsorLinker.cs" />
   </ItemGroup>
 
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="all" />
     <PackageReference Include="NuGetizer" Version="1.0.1" Pack="false" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.0.1" Pack="false" />
-    <PackageReference Include="Devlooped.SponsorLink" Version="0.10.3" />
+    <!--<PackageReference Include="Devlooped.SponsorLink" Version="0.10.2" />-->
   </ItemGroup>
 
   <ItemGroup>