Bump rbs from 3.9.0 to 3.9.1 in /steep

Bumps [rbs](https://github.com/ruby/rbs) from 3.9.0 to 3.9.1.
- [Release notes](https://github.com/ruby/rbs/releases)
- [Changelog](https://github.com/ruby/rbs/blob/master/CHANGELOG.md)
- [Commits](v3.9.0...v3.9.1)

---
updated-dependencies:
- dependency-name: rbs
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

steep/Gemfile

@@ -1,4 +1,4 @@
 source "https://rubygems.org"
 
-gem "rbs", "~> 3.9.pre"
+gem "rbs", "~> 3.9"
 gem "steep", "~> 1.10"

steep/Gemfile.lock

@@ -42,7 +42,7 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    rbs (3.9.0)
+    rbs (3.9.1)
       logger
     securerandom (0.4.1)
     steep (1.10.0)
@@ -76,7 +76,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  rbs (~> 3.9.pre)
+  rbs (~> 3.9)
   steep (~> 1.10)
 
 BUNDLED WITH