Bump puma from 3.11.3 to 3.12.2

Bumps [puma](https://github.com/puma/puma) from 3.11.3 to 3.12.2.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](https://github.com/puma/puma/compare/v3.11.3...v3.12.2)

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -157,7 +157,7 @@ GEM
     popper_js (1.14.5)
     powerpack (0.1.1)
     public_suffix (3.0.2)
-    puma (3.11.3)
+    puma (3.12.2)
     rack (2.0.7)
     rack-canonical-host (0.2.3)
       addressable (> 0, < 3)
@@ -286,7 +286,7 @@ DEPENDENCIES
   jquery-rails
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.7)
+  puma (~> 3.12)
   rack-canonical-host
   rails (~> 5.1.6.2)
   recaptcha