[dotnet] configure local nuget package cache

.editorconfig

@@ -14,7 +14,7 @@ indent_size = 4
 indent_style = space
 tab_width = 4
 
-[*.{md,json,yml,props,csproj}]
+[*.{md,json,yml,xml,props,csproj}]
 
 indent_size = 2
 tab_width = 2

.gitignore

@@ -26,6 +26,7 @@ arm64/
 *.userosscache
 *.sln.docstates
 
+.packages
 packages/
 *.nupkg
 .nuget/

nuget.config

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<configuration>
+  <config>
+    <add key="globalPackagesFolder" value=".packages" />
+  </config>
+
+  <packageSources>
+    <clear />
+    <add key="Nuget" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+
+  <packageSourceMapping>
+    <packageSource key="Nuget">
+      <package pattern="*" />
+    </packageSource>
+  </packageSourceMapping>
+</configuration>