Bump rdoc from 7.1.0 to 7.2.0 (#3204)

Bumps [rdoc](https://github.com/ruby/rdoc) from 7.1.0 to 7.2.0.
- [Release notes](https://github.com/ruby/rdoc/releases)
- [Changelog](https://github.com/ruby/rdoc/blob/master/History.rdoc)
- [Commits](ruby/rdoc@v7.1.0...v7.2.0)

---
updated-dependencies:
- dependency-name: rdoc
  dependency-version: 7.2.0
  dependency-type: direct:production
  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>

Author: dependabot[bot]

Gemfile.lock

@@ -49,7 +49,7 @@ GEM
     racc (1.8.1)
     rainbow (3.1.1)
     rake (13.3.1)
-    rdoc (7.1.0)
+    rdoc (7.2.0)
       erb
       psych (>= 4.0.0)
       tsort