[GH Usage] Changed to ReadOnly collections

Author: mogah

src/NuGetGallery.Core/GitHub/GitHubUsageConfiguration.cs

@@ -9,9 +9,9 @@ namespace NuGetGallery
 {
     public class GitHubUsageConfiguration : IGitHubUsageConfiguration
     {
-        private readonly Dictionary<string, NuGetPackageGitHubInformation> _nuGetPackagesGitHubDependencies;
+        private readonly IReadOnlyDictionary<string, NuGetPackageGitHubInformation> _nuGetPackagesGitHubDependencies;
 
-        public GitHubUsageConfiguration(IReadOnlyList<RepositoryInformation> repositories)
+        public GitHubUsageConfiguration(IReadOnlyCollection<RepositoryInformation> repositories)
         {
             if (repositories == null)
             {
@@ -36,7 +36,7 @@ public NuGetPackageGitHubInformation GetPackageInformation(string packageId)
             return NuGetPackageGitHubInformation.Empty;
         }
 
-        private static Dictionary<string, NuGetPackageGitHubInformation> GetNuGetPackagesDependents(IReadOnlyList<RepositoryInformation> repositories)
+        private static IReadOnlyDictionary<string, NuGetPackageGitHubInformation> GetNuGetPackagesDependents(IReadOnlyCollection<RepositoryInformation> repositories)
         {
             var dependentsPerPackage = new Dictionary<string, List<RepositoryInformation>>(StringComparer.InvariantCultureIgnoreCase);
             foreach (var repo in repositories)

src/NuGetGallery.Services/Storage/ContentObjectService.cs

@@ -49,7 +49,7 @@ await Refresh<SymbolsConfiguration>(ServicesConstants.ContentNames.SymbolsConfig
                await Refresh<TyposquattingConfiguration>(ServicesConstants.ContentNames.TyposquattingConfiguration) ??
                new TyposquattingConfiguration();
 
-            var reposCache = await Refresh<IReadOnlyList<RepositoryInformation>>(ServicesConstants.ContentNames.NuGetPackagesGitHubDependencies) ??
+            var reposCache = await Refresh<IReadOnlyCollection<RepositoryInformation>>(ServicesConstants.ContentNames.NuGetPackagesGitHubDependencies) ??
                              Array.Empty<RepositoryInformation>();
 
             GitHubUsageConfiguration = new GitHubUsageConfiguration(reposCache);