Reminder: please update FLIP document to latest status

[Yu Li]

Dear all,

While checking 1.10 release progress, we find some FLIPs have already been
accepted through voting, but still marked as "Under Discussion" in wiki
document (eg. FLIP-68), and some marked as implementing but lack of JIRA
link (eg. FLIP-64). So just a reminder to our FLIP authors/owners, that
please check the FLIP document and update it to the latest status when
possible. Many thanks.

Best Regards,
Yu