Merge pull request #840 from dxw/renovate/puma-6.x-lockfile

Update dependency puma to v6.6.0

Author: renovate[bot]

Gemfile.lock

@@ -223,7 +223,7 @@ GEM
       date
       stringio
     public_suffix (6.0.1)
-    puma (6.5.0)
+    puma (6.6.0)
       nio4r (~> 2.0)
     racc (1.8.1)
     rack (3.1.8)