Bump rack-protection in /hooks/ruby/configuring-your-server

Bumps [rack-protection](https://github.com/sinatra/sinatra) from 1.5.2 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)

---
updated-dependencies:
- dependency-name: rack-protection
  dependency-type: indirect
...

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

Author: dependabot[bot]

hooks/ruby/configuring-your-server/Gemfile.lock

@@ -3,7 +3,7 @@ GEM
   specs:
     json (1.8.3)
     rack (1.6.13)
-    rack-protection (1.5.2)
+    rack-protection (1.5.5)
       rack
     sinatra (1.3.6)
       rack (~> 1.4)