[tz] Estimate for a new tzdb release with Brazil rules.

[Paul Eggert]

Rodrigo Brüning Wessler wrote:
> For many reasons, use the development repository is not easy for us.

Whatever the reasons are, in the long run it should be better to fix those 
bottlenecks than to worry overmuch about whether there will be an official 
release now or some weeks from now. There shouldn't be that much trouble testing 
and/or using a version named "2019a-14-g9e498e2" as opposed to testing and/or 
using a version named "2019b".