Bump split from 3.4.1 to 4.0.1

Bumps [split](https://github.com/splitrb/split) from 3.4.1 to 4.0.1.
- [Release notes](https://github.com/splitrb/split/releases)
- [Changelog](https://github.com/splitrb/split/blob/main/CHANGELOG.md)
- [Commits](splitrb/split@v3.4.1...v4.0.1)

---
updated-dependencies:
- dependency-name: split
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -6,17 +6,17 @@ GEM
     rack (2.2.3)
     rack-protection (2.1.0)
       rack
-    redis (4.1.3)
-    ruby2_keywords (0.0.2)
-    simple-random (1.0.3)
+    redis (4.5.1)
+    ruby2_keywords (0.0.5)
+    rubystats (0.3.0)
     sinatra (2.1.0)
       mustermann (~> 1.0)
       rack (~> 2.2)
       rack-protection (= 2.1.0)
       tilt (~> 2.0)
-    split (3.4.1)
-      redis (>= 2.1)
-      simple-random (>= 0.9.3)
+    split (4.0.1)
+      redis (>= 4.2)
+      rubystats (>= 0.3.0)
       sinatra (>= 1.2.6)
     tilt (2.0.10)