Bump puma from 5.2.1 to 5.3.2 (PR #879)

Bumps [puma](https://github.com/puma/puma) from 5.2.1 to 5.3.2.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](https://github.com/puma/puma/compare/v5.2.1...v5.3.2)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -312,7 +312,7 @@ GEM
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
     mysql2 (0.5.3)
-    nio4r (2.5.5)
+    nio4r (2.5.7)
     nokogiri (1.11.4)
       mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
@@ -336,7 +336,7 @@ GEM
       binding_of_caller (~> 1.0)
       pry (~> 0.13)
     public_suffix (4.0.6)
-    puma (5.2.1)
+    puma (5.3.2)
       nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)