Bump stringio from 3.0.1 to 3.0.6 (#25)

Bumps [stringio](https://github.com/ruby/stringio) from 3.0.1 to 3.0.6.
- [Release notes](https://github.com/ruby/stringio/releases)
- [Changelog](https://github.com/ruby/stringio/blob/master/NEWS.md)
- [Commits](ruby/stringio@v3.0.1...v3.0.6)

---
updated-dependencies:
- dependency-name: stringio
  dependency-type: indirect
...

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

Gemfile.lock

@@ -31,7 +31,7 @@ GEM
     rubocop-ast (1.16.0)
       parser (>= 3.1.1.0)
     ruby-progressbar (1.11.0)
-    stringio (3.0.1)
+    stringio (3.0.6)
     unicode-display_width (2.1.0)
 
 PLATFORMS