Hello, 

To you update your config file, 

Firstly login to your Odoo.sh then you will get multiple options like History, SHELL, Editor. Then here you need to click on the SHELL tab.

Then you will get a shell access of Odoo.sh. So in order to get your config file you can go through the below path,

"/home/odoo/.config/odoo/odoo.conf"

Then inside the config file you can make your required changes