Add Renovate

[rickyp-uber]

Since this product doesn't get touched a whole ton, it would be good to run renovate on it. The only sticking point here is that we may need to move the flow-bin dependency out to a peer dependency or lock it to something lower.

Flow doesn't have statistics on what versions are currently in use so it's hard to know what the lower bound of support is.

Flow also isn't at a major build so we can be broken at any time.

The other choice is to always depend on the latest flow-bin and if someone is using an older flow-bin and we output something that isn't compatible, it's up to them to resolve it. This is probably the easiest from a maintenance standpoint until we have major builds that are backwards compatible.