Merge pull request #1634 from coderdojo-japan/dependabot/bundler/puma-6.4.3

Bump puma from 6.4.2 to 6.4.3

Author: yasulab

Gemfile.lock

@@ -303,7 +303,7 @@ GEM
       binding_of_caller (~> 1.0)
       pry (~> 0.13)
     public_suffix (6.0.1)
-    puma (6.4.2)
+    puma (6.4.3)
       nio4r (~> 2.0)
     puma_worker_killer (1.0.0)
       bigdecimal (>= 2.0)