Update docfx.json

Author: gewarren

docfx.json

@@ -149,6 +149,7 @@
       "open_to_public_contributors": {
         "api/Microsoft.Extensions**": false,
         "api/System.Composition**": false,
+        "api/System.Formats.Asn1**": false,
         "api/System.Formats.Cbor**": false,
         "api/System.Formats.Nrbf**": false,
         "api/System.Net.ServerSentEvents**": false,