Add nuget.config

Author: David Nierman

src/ReactiveDomain.sln

@@ -31,6 +31,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		build.props = build.props
 		..\tools\CreateDebugNuget.ps1 = ..\tools\CreateDebugNuget.ps1
 		..\tools\CreateNuget.ps1 = ..\tools\CreateNuget.ps1
+		nuget.config = nuget.config
 		..\package.bat = ..\package.bat
 		..\.github\workflows\pr-checks.yml = ..\.github\workflows\pr-checks.yml
 		..\publish.bat = ..\publish.bat

src/nuget.config

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
+    <clear />
+    <add key="nuget" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>