Bump puma from 4.3.3 to 4.3.5 in /apps/epp_proxy/priv/test_backend_app

Bumps [puma](https://github.com/puma/puma) from 4.3.3 to 4.3.5.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](https://github.com/puma/puma/commits)

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

Author: dependabot[bot]

apps/epp_proxy/priv/test_backend_app/Gemfile.lock

@@ -2,7 +2,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     nio4r (2.5.2)
-    puma (4.3.3)
+    puma (4.3.5)
       nio4r (~> 2.0)
     rack (2.0.8)
     rack-unreloader (1.7.0)