Update rubocop-performance requirement from 1.14.3 to 1.15.0

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](https://github.com/rubocop/rubocop-performance/compare/v1.14.3...v1.15.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/Gemfile b/Gemfile
index 09921c9c..e3dac987 100644
--- a/Gemfile
+++ b/Gemfile
@@ -16,7 +16,7 @@ group :development do
   gem "rspec-core", "~> 3.0"
   gem "rspec-expectations", "~> 3.0"
   gem "rspec-mocks", "~> 3.0"
-  gem "rubocop-performance", "1.14.3"
+  gem "rubocop-performance", "1.15.0"
   gem "rubocop-rspec"
 end