Bump rack-protection from 1.5.3 to 1.5.5

Bumps [rack-protection](https://github.com/sinatra/sinatra) from 1.5.3 to 1.5.5.
- [Release notes](https://github.com/sinatra/sinatra/releases)
- [Changelog](https://github.com/sinatra/sinatra/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sinatra/sinatra/commits)

Author: dependabot[bot]

Gemfile.lock

@@ -18,8 +18,8 @@ GEM
     nio4r (2.5.8)
     puma (5.5.2)
       nio4r (~> 2.0)
-    rack (1.6.4)
-    rack-protection (1.5.3)
+    rack (1.6.13)
+    rack-protection (1.5.5)
       rack
     rest-client (2.1.0)
       http-accept (>= 1.7.0, < 2.0)