Bump erb from 6.0.2 to 6.0.4 in /docs (#453)

Bumps [erb](https://github.com/ruby/erb) from 6.0.2 to 6.0.4.
- [Release notes](https://github.com/ruby/erb/releases)
- [Changelog](https://github.com/ruby/erb/blob/master/NEWS.md)
- [Commits](ruby/erb@v6.0.2...v6.0.4)

---
updated-dependencies:
- dependency-name: erb
  dependency-version: 6.0.4
  dependency-type: indirect
...

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

Author: dependabot[bot]

docs/Gemfile.lock

@@ -132,7 +132,7 @@ GEM
       irb (~> 1.10)
       reline (>= 0.3.8)
     drb (2.2.3)
-    erb (6.0.2)
+    erb (6.0.4)
     erubi (1.13.1)
     globalid (1.3.0)
       activesupport (>= 6.1)