deps: Update rbs to v3.4

Since Ruby 3.4, abbrev gem has became the bundled gem.  But old rbs gem
does not depend on it.  This updates rbs gem to v3.4, which depends on
abbrev gem explicitly.

Author: tk0miya

Gemfile.lock

@@ -8,6 +8,7 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
+    abbrev (0.1.2)
     actioncable (7.0.5)
       actionpack (= 7.0.5)
       activesupport (= 7.0.5)
@@ -155,7 +156,8 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rbs (3.1.0)
+    rbs (3.4.3)
+      abbrev
     securerandom (0.2.2)
     steep (1.4.0)
       activesupport (>= 5.1)