Fixed build warnings about System.Net.Http version issues

Author: AArnott

LibGit2Sharp/Core/ManagedHttpSmartSubtransport.cs

@@ -69,16 +69,9 @@ public ManagedHttpSmartSubtransportStream(ManagedHttpSmartSubtransport parent, s
 
             private HttpClientHandler CreateClientHandler()
             {
-#if !NETFRAMEWORK
                 var httpClientHandler = new HttpClientHandler();
                 httpClientHandler.SslProtocols |= SslProtocols.Tls12;
                 httpClientHandler.ServerCertificateCustomValidationCallback = CertificateValidationProxy;
-#else
-                var httpClientHandler = new WebRequestHandler();
-                httpClientHandler.ServerCertificateValidationCallback = CertificateValidationProxy;
-
-                ServicePointManager.SecurityProtocol |= SecurityProtocolType.Tls12;
-#endif
 
                 httpClientHandler.AllowAutoRedirect = false;
 

LibGit2Sharp/LibGit2Sharp.csproj

@@ -31,18 +31,11 @@
     <Service Include="{508349b6-6b84-4df5-91f0-309beebad82d}" /> <!-- Needed for T4 generation -->
   </ItemGroup>
 
-  <ItemGroup>
-    <Reference Include="System.Net.Http" />
-    <Reference Include="System.Net.Http.WebRequest" />
-  </ItemGroup>
-
   <ItemGroup>
     <PackageReference Include="LibGit2Sharp.NativeBinaries" Version="[2.0.305]" PrivateAssets="none" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="all" />
     <PackageReference Include="Nerdbank.GitVersioning" Version="3.0.50" PrivateAssets="all" />
-    <PackageReference Include="System.Net.Http" Version="4.3.4">
-      <ExcludeAssets>All</ExcludeAssets>
-    </PackageReference>
+    <PackageReference Include="System.Net.Http" Version="4.3.4" />
   </ItemGroup>
 
   <Import Project="..\Targets\CodeGenerator.targets" />