Update rspec requirement from ~> 2.14.1 to ~> 3.13.0

Updates the requirements on [rspec](https://github.com/rspec/rspec-metagem) to permit the latest version.
- [Commits](rspec/rspec-metagem@v2.14.1...v3.13.0)

---
updated-dependencies:
- dependency-name: rspec
  dependency-version: 3.13.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

packaging.gemspec

@@ -15,7 +15,7 @@ Gem::Specification.new do |gem|
 
   gem.required_ruby_version = '>= 2.0.0'
 
-  gem.add_development_dependency('rspec', ['~> 2.14.1'])
+  gem.add_development_dependency('rspec', '~> 3.13.0')
   gem.add_development_dependency('rubocop', ['~> 0.24.1'])
   gem.add_development_dependency('pry-byebug')
   gem.add_runtime_dependency('rake', ['>= 12.3'])