[w3c/webauthn] 19e76a: update token binding citation

  Branch: refs/heads/jeffh-fix-1086-tokbind-ref
  Home:   https://github.com/w3c/webauthn
  Commit: 19e76a39b736aaf29be81d0b45f1c114f9d9e3f5
      https://github.com/w3c/webauthn/commit/19e76a39b736aaf29be81d0b45f1c114f9d9e3f5
  Author: JeffH <Jeff.Hodges@KingsMountain.com>
  Date:   2018-09-26 (Wed, 26 Sep 2018)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  update token binding citation



      **NOTE:** This service has been marked for deprecation: https://developer.github.com/changes/2018-04-25-github-services-deprecation/

      Functionality will be removed from GitHub.com on January 31st, 2019.