Check assemblies reference System.Net.Http v4.0

Check all GitHub.* assemblies reference System.Net.Http v4.0.0.0.

Author: jcansdale

test/GitHub.VisualStudio.UnitTests/GitHubAssemblyTests.cs

@@ -1,4 +1,5 @@
-using System.IO;
+using System;
+using System.IO;
 using System.Reflection;
 using NUnit.Framework;
 
@@ -15,6 +16,19 @@ public void GitHub_Assembly_Should_Not_Reference_DesignTime_Assembly(string asse
         }
     }
 
+    [Theory]
+    public void GitHub_Assembly_Should_Not_Reference_System_Net_Http_Above_4_0(string assemblyFile)
+    {
+        var asm = Assembly.LoadFrom(assemblyFile);
+        foreach (var referencedAssembly in asm.GetReferencedAssemblies())
+        {
+            if (referencedAssembly.Name == "System.Net.Http")
+            {
+                Assert.That(referencedAssembly.Version, Is.EqualTo(new Version("4.0.0.0")));
+            }
+        }
+    }
+
     [DatapointSource]
     string[] GitHubAssemblies => Directory.GetFiles(AssemblyDirectory, "GitHub.*.dll");