upgraded consul package and restored Net461 conditional compilation (#127)

Author: GimmeDaKitty

src/Winton.Extensions.Configuration.Consul/Winton.Extensions.Configuration.Consul.csproj

@@ -27,10 +27,15 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Consul" Version="0.7.2.6" />
+    <PackageReference Include="Consul" Version="1.6.10.4" />
     <PackageReference Include="Microsoft.Extensions.Configuration" Version="3.0.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="3.0.0" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="All" />
   </ItemGroup>
 
+  <ItemGroup Condition=" '$(TargetFramework)' == 'net461' ">
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Net.Http.WebRequest" />
+  </ItemGroup>
+
 </Project>