Log Message:
www/ruby-puma: update to 3.12.0

## 3.12.0 / 2018-07-13

* 5 features:
  * You can now specify which SSL ciphers the server should support, default is \ 
unchanged (#1478)
  * The setting for Puma's `max_threads` is now in `Puma.stats` (#1604)
  * Pool capacity is now in `Puma.stats` (#1579)
  * Installs restricted to Ruby 2.2+ (#1506)
  * `--control` is now deprecated in favor of `--control-url` (#1487)

* 2 bugfixes:
  * Workers will no longer accept more web requests than they have capacity to \ 
process. This prevents an issue where one worker would accept lots of requests \ 
while starving other workers (#1563)
  * In a test env puma now emits the stack on an exception (#1557)