Merge pull request #754 from dotnet/add-dotnet11-folder

Add 11.0 folder with global.json for .NET 11 previews

Author: jfversluis

11.0/global.json

@@ -0,0 +1,7 @@
+{
+  "sdk": {
+    "version": "11.0.100-preview.3.26207.106",
+    "rollForward": "latestFeature",
+    "allowPrerelease": true
+  }
+}