Upgrade System.Net.Http (#7003)

Author: xavierdecoster

src/NuGetGallery/NuGetGallery.csproj

@@ -2381,7 +2381,7 @@
       <Version>4.3.0</Version>
     </PackageReference>
     <PackageReference Include="System.Net.Http">
-      <Version>4.3.1</Version>
+      <Version>4.3.4</Version>
     </PackageReference>
     <PackageReference Include="NuGet.StrongName.WebActivator">
       <Version>1.4.4</Version>