Bump puma from 4.3.8 to 4.3.9

Bumps [puma](https://github.com/puma/puma) from 4.3.8 to 4.3.9.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v4.3.8...v4.3.9)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -221,7 +221,7 @@ GEM
     msgpack (1.3.1)
     multi_xml (0.6.0)
     multipart-post (2.1.1)
-    nio4r (2.5.2)
+    nio4r (2.5.8)
     nokogiri (1.11.5)
       mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
@@ -239,7 +239,7 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     public_suffix (4.0.6)
-    puma (4.3.8)
+    puma (4.3.9)
       nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)