[keyserver] Add Redis to docker-compose.yml

Summary:
Tried to lock to specific versions here.

Depends on D3850

Test Plan:
in concert with D3850, I tested that yarn update-geoip worked inside the Docker image (it accesses Redis, admittedly for no good reason)

tested and made sure it was able to connect with cd keyserver && docker-compose up --build

Reviewers: palys-swm, jimpo

Reviewed By: palys-swm

Subscribers: Adrian, atul, karol-bisztyga, yayabosh

Differential Revision: https://phabricator.ashoat.com/D3851