Update rubocop-performance requirement from ~> 1.25.0 to ~> 1.26.0

Updates the requirements on [rubocop-performance](https://github.com/rubocop/rubocop-performance) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-performance/releases)
- [Changelog](https://github.com/rubocop/rubocop-performance/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-performance@v1.25.0...v1.26.0)

---
updated-dependencies:
- dependency-name: rubocop-performance
  dependency-version: 1.26.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

Gemfile

@@ -19,7 +19,7 @@ group :test do
   gem "oj", "~> 3.14" if ENV["WITH_OJ_GEM"] == "true"
   gem "rspec", "~> 3.13.0"
   gem "rubocop", "~> 1.78.0"
-  gem "rubocop-performance", "~> 1.25.0"
+  gem "rubocop-performance", "~> 1.26.0"
   gem "simplecov", "~> 0.22.0"
   gem "simplecov-console", "~> 0.9.1"
 end