Bump puma from 4.3.7 to 4.3.8

Bumps [puma](https://github.com/puma/puma) from 4.3.7 to 4.3.8.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v4.3.7...v4.3.8)

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

Gemfile.lock

@@ -79,14 +79,16 @@ GEM
       mimemagic (~> 0.3.2)
     method_source (1.0.0)
     middleware (0.1.0)
-    mimemagic (0.3.5)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.5.0)
     minitest (5.14.3)
     msgpack (1.4.2)
     multi_json (1.15.0)
     mysql2 (0.5.3)
-    nio4r (2.5.5)
+    nio4r (2.5.7)
     nokogiri (1.11.1)
       mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
@@ -95,7 +97,7 @@ GEM
       middleware
       thor
       thread_safe
-    puma (4.3.7)
+    puma (4.3.8)
       nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)