Bump debug from 1.3.4 to 1.4.0 (#15835)

Bumps [debug](https://github.com/ruby/debug) from 1.3.4 to 1.4.0.
- [Release notes](https://github.com/ruby/debug/releases)
- [Commits](https://github.com/ruby/debug/compare/v1.3.4...v1.4.0)

---
updated-dependencies:
- dependency-name: debug
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -187,7 +187,7 @@ GEM
       msgpack
     dead_end (1.1.7)
     debase-ruby_core_source (0.10.12)
-    debug (1.3.4)
+    debug (1.4.0)
       irb (>= 1.3.6)
       reline (>= 0.2.7)
     derailed_benchmarks (2.1.1)