This is not an MM:S plugin; it's a VSP. I'm posting it here anyway.
This will re-enable the -maxplayers command line parameter, up to 64.
Note that three things can still override this limit:
- Having a lower maxplayers set on command line with the -maxplayers_override parameter
- Having "maxplayers" defined as a lower value for the current game/mode in gamemodes_server.txt
- The map not having enough spawn points. (The default maps each have 30 unless you use another plugin to add more.)
To install, just extract the zip to the csgo game directory. It should put the vdf under addons/ and the other files under addons/csgomax/.
The txt file attached is the source code. You don't need it on the server.