Bump irb from 1.14.3 to 1.15.1

Bumps [irb](https://github.com/ruby/irb) from 1.14.3 to 1.15.1.
- [Release notes](https://github.com/ruby/irb/releases)
- [Commits](ruby/irb@v1.14.3...v1.15.1)

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

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

Gemfile.lock

@@ -38,7 +38,8 @@ GEM
     i18n (1.14.6)
       concurrent-ruby (~> 1.0)
     io-console (0.8.0)
-    irb (1.14.3)
+    irb (1.15.1)
+      pp (>= 0.6.0)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
     json (2.9.1)
@@ -51,13 +52,16 @@ GEM
     parser (3.3.7.0)
       ast (~> 2.4.1)
       racc
-    psych (5.2.2)
+    pp (0.6.2)
+      prettyprint
+    prettyprint (0.2.0)
+    psych (5.2.3)
       date
       stringio
     racc (1.8.1)
     rainbow (3.1.1)
     rake (13.2.1)
-    rdoc (6.10.0)
+    rdoc (6.11.0)
       psych (>= 4.0.0)
     regexp_parser (2.10.0)
     reissue (0.3.3)