v60.1.0-alpha.197

Change Log

1. Upgraded J2N dependency to version 2.0.0-beta-0001
2. Fixed methods that broke during the upgrade:
   • ToAppendable() > AsAppendable() from StringBuilderExtensions
   • ToCharSequence() > AsCharSequence() from StringExtensions, StringBuilderExtensions, and CharArrayExtensions
   • ToUnmodifiableXXX() > AsReadOnly() from ListExtensions, DictionaryExtensions, CollectionExtensions, and SetExtensions