[GH Usage] Added license header

Author: mogah

src/NuGetGallery.Core/GitHub/GitHubUsageConfiguration.cs

@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
 using System.Collections.Generic;
 using System.Linq;
 

src/NuGetGallery.Core/GitHub/IGitHubUsageConfiguration.cs

@@ -1,4 +1,7 @@
-namespace NuGetGallery.GitHub
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace NuGetGallery.GitHub
 {
     public interface IGitHubUsageConfiguration
     {

src/NuGetGallery.Core/GitHub/NuGetPackageGitHubInformation.cs

@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
 using System.Collections.Generic;
 using System.Linq;
 

src/NuGetGallery.Core/GitHub/RepositoryInformation.cs

@@ -1,4 +1,7 @@
-using Newtonsoft.Json;
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Newtonsoft.Json;
 using System;
 using System.Collections.Generic;
 

tests/NuGetGallery.Core.Facts/GitHub/GitHubUsageConfigurationFacts.cs

@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using Xunit;