Use current working directory to resolve file path

Author: MaggieKimani1

src/Microsoft.OpenApi/Reader/Services/DefaultStreamLoader.cs

@@ -56,7 +56,16 @@ public Stream Load(Uri uri)
         /// <exception cref="ArgumentException"></exception>
         public async Task<Stream> LoadAsync(Uri uri)
         {
-            var absoluteUri = new Uri(baseUrl, uri);
+            Uri absoluteUri;
+            if (baseUrl.Equals(OpenApiConstants.BaseRegistryUri))
+            {
+                // use current working directory
+                absoluteUri = new Uri(Directory.GetCurrentDirectory() + uri);
+            }
+            else
+            {
+                absoluteUri = new Uri(baseUrl, uri);
+            }
 
             switch (absoluteUri.Scheme)
             {