Add explicit require dep phpseclib/phpseclib. Update minor releases o…

[melroy89]

• Add phpseclib/phpseclib package explicitly to composer.json require now, since we depend on it. (it used to be an indirect dependency --> BAD practice)
• Update minor PHP packages

Fixes:

{"message":"Uncaught PHP Exception Error: \"Class \"phpseclib3\\Crypt\\RSA\" not found\" at KeysGenerator.php line 14","context":{"exception":{"class":"Error","message":"Class \"phpseclib3\\Crypt\\RSA\" not found","code":0,"file":"/var/www/kbin.melroy.org/html/src/Service/ActivityPub/KeysGenerator.php:14"}},"level":500,"level_name":"CRITICAL","channel":"request","datetime":"2024-09-19T16:44:29.966453+02:00","extra":{}}

This was caused by PR: #1101 (comment) (which only removed activitypub package, but also removed this package). However we did needed this phpseclib3 package as well, but.. it was never explicit stated as a require dependency in composer. Hence it was auto-deleted.