chore: Update rubocop requirement from = 1.30.1 to = 1.31.0 (#932)

* chore: Update rubocop requirement from = 1.30.1 to = 1.31.0

Updates the requirements on [rubocop](https://github.com/rubocop/rubocop) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v1.30.1...v1.31.0)

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

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

* update

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

Author: dependabot[bot]

.rubocop.yml

@@ -51,7 +51,7 @@ Style/StringConcatenation:
   Enabled: false
 Lint/NonDeterministicRequireOrder:
   Enabled: false
-Gemspec/DateAssignment:
+Gemspec/DeprecatedAttributeAssignment:
   Enabled: true
 Layout/LineEndStringConcatenationIndentation:
   Enabled: true

appium_lib.gemspec

@@ -24,7 +24,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'posix-spawn', '~> 0.3'
   s.add_development_dependency 'pry'
   s.add_development_dependency 'rake', '~> 13.0'
-  s.add_development_dependency 'rubocop', '1.30.1'
+  s.add_development_dependency 'rubocop', '1.31.0'
   s.add_development_dependency 'spec', '~> 5.3', '>= 5.3.4'
   s.add_development_dependency 'yard', '~> 0.9.11'