Bump the rubocop group in /updater with 1 update (#1056)

Bumps the rubocop group in /updater with 1 update: [rubocop-performance](https://github.com/rubocop/rubocop-performance).


Updates `rubocop-performance` from 1.20.2 to 1.21.0
- [Release notes](https://github.com/rubocop/rubocop-performance/releases)
- [Changelog](https://github.com/rubocop/rubocop-performance/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-performance@v1.20.2...v1.21.0)

---
updated-dependencies:
- dependency-name: rubocop-performance
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: rubocop
...

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

updater/Gemfile.lock

@@ -265,9 +265,9 @@ GEM
       unicode-display_width (>= 2.4.0, < 3.0)
     rubocop-ast (1.31.2)
       parser (>= 3.3.0.4)
-    rubocop-performance (1.20.2)
+    rubocop-performance (1.21.0)
       rubocop (>= 1.48.1, < 2.0)
-      rubocop-ast (>= 1.30.0, < 2.0)
+      rubocop-ast (>= 1.31.1, < 2.0)
     rubocop-sorbet (0.8.0)
       rubocop (>= 0.90.0)
     ruby-progressbar (1.13.0)