Relax bounds for rapid 0.1.4

[f-f]

Here's a PR for this in rapid's repo, but sadly:

Ertugrul Söylemez died unexpectedly on May 12.

The PR is 6 months old, so I believe the correct bounds today would be (note: as the matrix shows the current bounds prevent a build plan for GHC 8.4 and 8.6):

async >= 2.1 && < 2.3,
base >= 4.8 && < 4.13,
containers >= 0.5 && < 0.7,
foreign-store == 0.2.*,
stm >= 2.4 && < 2.6

[gwils]

Thanks for reporting this. I've made the revision.

[f-f]

Thanks @gwils!