Bump stringio from 3.0.1 to 3.1.0

Bumps [stringio](https://github.com/ruby/stringio) from 3.0.1 to 3.1.0.
- [Release notes](https://github.com/ruby/stringio/releases)
- [Changelog](https://github.com/ruby/stringio/blob/master/NEWS.md)
- [Commits](ruby/stringio@v3.0.1...v3.1.0)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -26,7 +26,7 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.11.0)
     rspec-support (3.11.0)
-    stringio (3.0.1)
+    stringio (3.1.0)
 
 PLATFORMS
   ruby