www/owncast: Update to 0.0.13

ChangeLog: https://github.com/owncast/owncast/releases/tag/v0.0.13

Added

• Add Fediverse, Matrix and XMPP social links
• Changed
• Do not log inactionable Federated resolution/verification errors
• Improve chat input accessibility
• Treat fediverse usernames as case-insensitive
• Sanitize user submitted values before logging
• Username length is now validated server-side
• Do not allow multiple Fediverse auth attempts.

Fixed

• Manually authored social posts are always set to followers-only
• Fix superfluous response.WriteHeader call error
• Fix possible security exploit for those with Moderator access.
• Messages table fixes to improve query performance
• Fix possible crash with Federated Undo request

PR: 271693
Reported by: clukas@firc.de
Approved by: de-freebsd@ctseuro.com (maintainer, timeout > 2 weeks)