Bump fakeredis from 0.8.0 to 0.9.2 (#12829)

Bumps [fakeredis](https://github.com/guilleiguaran/fakeredis) from 0.8.0 to 0.9.2.
- [Commits](guilleiguaran/fakeredis@v0.8.0...v0.9.2)

---
updated-dependencies:
- dependency-name: fakeredis
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Ryan McNeil <ryan.mcneil@oddball.io>

Gemfile.lock

@@ -400,8 +400,8 @@ GEM
       railties (>= 5.0.0)
     faker (3.1.1)
       i18n (>= 1.8.11, < 2)
-    fakeredis (0.8.0)
-      redis (~> 4.1)
+    fakeredis (0.9.2)
+      redis (~> 4.8)
     faraday (0.17.6)
       multipart-post (>= 1.2, < 3)
     faraday-http-cache (2.2.0)

lib/common/models/redis_store.rb

@@ -78,7 +78,7 @@ def self.pop(redis_key = nil)
     end
 
     def self.exists?(redis_key = nil)
-      redis_namespace.exists(redis_key)
+      redis_namespace.exists?(redis_key)
     end
 
     def self.create(attributes)