Bump rack-protection in /hooks/ruby/dismiss-review-server

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)

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

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

Author: dependabot[bot]

hooks/ruby/dismiss-review-server/Gemfile.lock

@@ -11,7 +11,7 @@ GEM
     mime-types-data (3.2016.0521)
     netrc (0.11.0)
     rack (1.6.13)
-    rack-protection (1.5.3)
+    rack-protection (1.5.5)
       rack
     rest-client (2.0.1)
       http-cookie (>= 1.0.2, < 2.0)