Bump puma from 4.3.8 to 4.3.12

Bumps [puma](https://github.com/puma/puma) from 4.3.8 to 4.3.12.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v4.3.8...v4.3.12)

---
updated-dependencies:
- dependency-name: puma
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -146,11 +146,11 @@ GEM
     mini_portile2 (2.4.0)
     minitest (5.14.0)
     msgpack (1.3.3)
-    nio4r (2.5.7)
+    nio4r (2.5.8)
     nokogiri (1.10.9)
       mini_portile2 (~> 2.4.0)
     pg (1.2.3)
-    puma (4.3.8)
+    puma (4.3.12)
       nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (1.1.0)