Bump rack-attack from 5.0.1 to 6.2.2

Bumps [rack-attack](https://github.com/kickstarter/rack-attack) from 5.0.1 to 6.2.2.
- [Release notes](https://github.com/kickstarter/rack-attack/releases)
- [Changelog](https://github.com/kickstarter/rack-attack/blob/master/CHANGELOG.md)
- [Commits](rack/rack-attack@v5.0.1...v6.2.2)

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

Author: dependabot-preview[bot]

Gemfile.lock

@@ -112,9 +112,9 @@ GEM
       pry (>= 0.9.11)
     puma (4.3.1)
       nio4r (~> 2.0)
-    rack (2.1.2)
-    rack-attack (5.0.1)
-      rack
+    rack (2.2.2)
+    rack-attack (6.2.2)
+      rack (>= 1.0, < 3)
     rack-cors (1.1.1)
       rack (>= 2.0.0)
     rack-protection (2.0.8.1)