Merge pull request #1603 from dotnet/dependabot/nuget/Rx.NET/Source/MSBuild.Sdk.Extras-3.0.38

Author: clairernovotny

Rx.NET/Source/global.json

@@ -1,5 +1,5 @@
 {
   "msbuild-sdks": {
-    "MSBuild.Sdk.Extras": "3.0.23"
+    "MSBuild.Sdk.Extras": "3.0.38"
   }
 }