Bump split from 3.3.0 to 3.3.1

Bumps [split](https://github.com/splitrb/split) from 3.3.0 to 3.3.1.
- [Release notes](https://github.com/splitrb/split/releases)
- [Changelog](https://github.com/splitrb/split/blob/master/CHANGELOG.md)
- [Commits](splitrb/split@v3.3.0...v3.3.1)

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

Author: dependabot-support

Gemfile.lock

@@ -5,14 +5,14 @@ GEM
     rack (2.0.6)
     rack-protection (2.0.5)
       rack
-    redis (4.0.3)
+    redis (4.1.0)
     simple-random (1.0.3)
     sinatra (2.0.5)
       mustermann (~> 1.0)
       rack (~> 2.0)
       rack-protection (= 2.0.5)
       tilt (~> 2.0)
-    split (3.3.0)
+    split (3.3.1)
       redis (>= 2.1)
       simple-random (>= 0.9.3)
       sinatra (>= 1.2.6)