Merge pull request #1451 from dotnet/dependabot/nuget/Rx.NET/Source/MSBuild.Sdk.Extras-3.0.22

Bump MSBuild.Sdk.Extras from 2.1.2 to 3.0.22 in /Rx.NET/Source

Rx.NET/Source/global.json

@@ -3,6 +3,6 @@
     "version": "5.0.100-preview"
   },
   "msbuild-sdks": {
-    "MSBuild.Sdk.Extras": "2.1.2"
+    "MSBuild.Sdk.Extras": "3.0.22"
   }
 }