Mention libmaxminddb in ext directions
Mention libmaxminddb in ext directions

maxmind/MaxMind-DB-Reader-php,jbboehr/MaxMind-DB-Reader-php,jbboehr/MaxMind-DB-Reader-php,jbboehr/MaxMind-DB-Reader-php,maxmind/MaxMind-DB-Reader-php,maxmind/MaxMind-DB-Reader-php