Bump rack-attack from 6.3.1 to 6.4.0 (#12408)

Bumps [rack-attack](https://github.com/rack/rack-attack) from 6.3.1 to 6.4.0.
- [Release notes](https://github.com/rack/rack-attack/releases)
- [Changelog](https://github.com/rack/rack-attack/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rack/rack-attack/compare/v6.3.1...v6.4.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile

@@ -71,7 +71,7 @@ gem "puma", "~> 5.1.1" # Puma is a simple, fast, threaded, and highly concurrent
 gem "pundit", "~> 2.1" # Object oriented authorization for Rails applications
 gem "pusher", "~> 1.4" # Ruby library for Pusher Channels HTTP API
 gem "pusher-push-notifications", "~> 1.3" # Pusher Push Notifications Ruby server SDK
-gem "rack-attack", "~> 6.3.1" # Used to throttle requests to prevent brute force attacks
+gem "rack-attack", "~> 6.4.0" # Used to throttle requests to prevent brute force attacks
 gem "rack-cors", "~> 1.1" # Middleware that will make Rack-based apps CORS compatible
 gem "rack-timeout", "~> 0.6" # Rack middleware which aborts requests that have been running for longer than a specified timeout
 gem "rails", "~> 6.0.3" # Ruby on Rails

Gemfile.lock

@@ -541,7 +541,7 @@ GEM
     raabro (1.4.0)
     racc (1.5.2)
     rack (2.2.3)
-    rack-attack (6.3.1)
+    rack-attack (6.4.0)
       rack (>= 1.0, < 3)
     rack-cors (1.1.1)
       rack (>= 2.0.0)
@@ -931,7 +931,7 @@ DEPENDENCIES
   pundit-matchers (~> 1.6)
   pusher (~> 1.4)
   pusher-push-notifications (~> 1.3)
-  rack-attack (~> 6.3.1)
+  rack-attack (~> 6.4.0)
   rack-cors (~> 1.1)
   rack-host-redirect (~> 1.3)
   rack-timeout (~> 0.6)