prometheus/MAINTAINERS.md

@brian-brazil is the main/default maintainer, some parts of the codebase have other maintainers:

* `cmd`
  * `promtool`: @simonpasquier
* `discovery`
  * `k8s`: @brancz
* `documentation`
  * `prometheus-mixin`: @beorn7
* `storage`
  * `remote`: @csmarchbanks, @cstyan, @bwplotka
* `tsdb`: @codesome, @krasi-georgiev, @bwplotka
* `web`
  * `ui`: @juliusv
* `Makefile` and related build configuration: @simonpasquier, @SuperQ

For the sake of brevity all subtrees are not explicitly listed. Due to the size
of this repository, the natural changes in focus of maintainers over time, and
nuances of where particular features live, this list will always be incomplete
and out of date. However the listed maintainer(s) should be able to direct a
PR/question to the right person.