Bump nio4r from 2.5.3 to 2.5.4 (#14837)

Bumps [nio4r](https://github.com/socketry/nio4r) from 2.5.3 to 2.5.4.
- [Release notes](https://github.com/socketry/nio4r/releases)
- [Changelog](https://github.com/socketry/nio4r/blob/master/CHANGES.md)
- [Commits](https://github.com/socketry/nio4r/compare/v2.5.3...v2.5.4)

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

Gemfile.lock

@@ -362,7 +362,7 @@ GEM
     net-scp (3.0.0)
       net-ssh (>= 2.6.5, < 7.0.0)
     net-ssh (6.1.0)
-    nio4r (2.5.3)
+    nio4r (2.5.4)
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
     nokogumbo (2.0.2)