chore: compilation error fixes

Author: bdominguez

src/UnityNuGet/JsonCommonExtensions.cs

@@ -42,7 +42,7 @@ public override void WriteJson(JsonWriter writer, VersionRange? value, JsonSeria
             public override VersionRange? ReadJson(JsonReader reader, Type objectType, VersionRange? existingValue, bool hasExistingValue, JsonSerializer serializer)
             {
                 string? s = (string?)reader.Value;
-                return VersionRange.Parse(s);
+                return VersionRange.Parse(s!);
             }
         }
     }

src/UnityNuGet/RegistryCache.cs

@@ -84,7 +84,7 @@ public RegistryCache(string rootPersistentFolder, Uri rootHttpUri, string unityS
             // Initialize target framework
             foreach (var registryTargetFramework in _targetFrameworks)
             {
-                registryTargetFramework.Framework = NuGetFramework.Parse(registryTargetFramework.Name);
+                registryTargetFramework.Framework = NuGetFramework.Parse(registryTargetFramework.Name!);
             }
 
             _sourceCacheContext = new SourceCacheContext();
@@ -388,7 +388,7 @@ private async Task BuildInternal()
                                     {
                                         _registry.TryGetValue(dependencyPackageMeta.Identity.Id, out var registryEntry);
 
-                                        var registryMinimumVersion = registryEntry?.Version?.MinVersion;
+                                        var registryMinimumVersion = registryEntry?.Version?.MinVersion!;
 
                                         NuGetVersion newVersion = registryMinimumVersion > dependencyPackageMeta.Identity.Version ? registryMinimumVersion : dependencyPackageMeta.Identity.Version;
 
@@ -400,7 +400,7 @@ private async Task BuildInternal()
 
                                 if (packageDependency != null)
                                 {
-                                    if (deps.VersionRange.MinVersion > packageDependency.VersionRange.MinVersion)
+                                    if (deps.VersionRange.MinVersion! > packageDependency.VersionRange.MinVersion!)
                                     {
                                         packageDependency = new PackageDependency(packageDependency.Id, deps.VersionRange);
                                         resolvedDeps = packageDependency;
@@ -425,7 +425,7 @@ private async Task BuildInternal()
                             var key = $"{_unityScope}.{depsId}";
                             if (!npmVersion.Dependencies.ContainsKey(key))
                             {
-                                npmVersion.Dependencies.Add(key, GetNpmVersion(resolvedDeps.VersionRange.MinVersion));
+                                npmVersion.Dependencies.Add(key, GetNpmVersion(resolvedDeps.VersionRange.MinVersion!));
                             }
                         }
                     }