Bump rbs from 3.7.0 to 3.8.1 in /steep

Bumps [rbs](https://github.com/ruby/rbs) from 3.7.0 to 3.8.1.
- [Release notes](https://github.com/ruby/rbs/releases)
- [Changelog](https://github.com/ruby/rbs/blob/master/CHANGELOG.md)
- [Commits](v3.7.0...v3.8.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

steep/Gemfile

@@ -1,4 +1,4 @@
 source "https://rubygems.org"
 
-gem "rbs", "~> 3.7.0"
+gem "rbs", "~> 3.8.1"
 gem "steep", "~> 1.9.2"

steep/Gemfile.lock

@@ -41,10 +41,10 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    rbs (3.7.0)
+    rbs (3.8.1)
       logger
     securerandom (0.4.1)
-    steep (1.9.2)
+    steep (1.9.3)
       activesupport (>= 5.1)
       concurrent-ruby (>= 1.1.10)
       csv (>= 3.0.9)
@@ -55,7 +55,7 @@ GEM
       logger (>= 1.3.0)
       parser (>= 3.1)
       rainbow (>= 2.2.2, < 4.0)
-      rbs (~> 3.7.0)
+      rbs (~> 3.8)
       securerandom (>= 0.1)
       strscan (>= 1.0.0)
       terminal-table (>= 2, < 4)
@@ -72,7 +72,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  rbs (~> 3.7.0)
+  rbs (~> 3.8.1)
   steep (~> 1.9.2)
 
 BUNDLED WITH