chore(deps): update rubocop-config digest to 64e4c81

Author: renovate[bot]

Gemfile

@@ -13,7 +13,7 @@ group :development do
   gem 'benchmark-ips'
   gem 'pry'
   gem 'pry-byebug'
-  gem 'rubocop-config', github: 'jgraichen/rubocop-config', ref: 'v12', require: false
+  gem 'rubocop-config', github: 'jgraichen/rubocop-config', ref: '64e4c81870e869a3bdd9ea3c49fd042b321dbfbd', require: false
 end
 
 group :test do