www/nginx: switch 3rd party module rtmp to Sergey Dryabzhinsky's fork

[diizzy]

Summary

Unfortunately the "sub"-fork based off Sergey's fork seems to be abandoned so let's go back to using Sergey's as it's more active than Arut's

PR: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=259246

Reference:
https://cgit.freebsd.org/ports/commit/www/nginx?id=cb9b1dfa80ef5b3d34c8ef664b8bb426ac0e47e4
https://github.com/sergey-dryabzhinsky/nginx-rtmp-module

Test Plan

Compile tested on FreeBSD 13.0-STABLE #1 stable/13-n247667-dc9094140c9 (amd64) (make, make check-plist)
Poudriere testport OK 12.2-RELEASE (amd64)

[arrowd]

LGTM change-wise, but didn't look into semantic correctness, that is whether one or another fork should be preferred. I'll leave this to the maintainer.

I also pinged upstream about new release tag: https://github.com/sergey-dryabzhinsky/nginx-rtmp-module/issues/313

[diizzy]

Committed as https://cgit.freebsd.org/ports/commit/?id=5491cb228aa9bd879edd68151d23ddf619302eee