`docker-compose up` suggested in `CONTRIBUTING.md`, but there is no `docker-compose.yml`

[saukrs]

The Contributing instructions say: https://github.com/prometheus/mysqld_exporter/blob/main/CONTRIBUTING.md#local-setup

Local setup

The easiest way to make a local development setup is to use Docker Compose.

docker-compose up
make
make test

The seemingly related file was deleted on Dec 9, 2020: cecdaea

Should the docker-compose.yml be added back, or should the instructions be updated in some way?