Bump minimum version of webmock to 3.8.0 (#897)
Bump minimum version of webmock to 3.8.0 (#897)

Bumps the minimum version of webmock to 3.8.0 which contains a fix for a
Ruby 2.7 warning. This last change makes the whole project completely
warning-free!

Co-authored-by: Brandur <00509e3a7b916a959d57487fb812a4576bfbffe3@brandur.org>

stripe/stripe-ruby