Update code owners

[waymobetta]

We should consider removing @jaekwon as code owner of this repo (to avoid unnecessary spamming for him) and then include both myself and @leohhhn (in addition to @moul), with @moul being the final review that is required.

TODO:

• remove @jaekwon as code owner (or keep if he is unbothered by the spam)
• add @leohhhn
• add @waymobetta