Update rake requirement from ~> 10.4 to ~> 13.0

Updates the requirements on [rake](https://github.com/ruby/rake) to permit the latest version.
- [Release notes](https://github.com/ruby/rake/releases)
- [Changelog](https://github.com/ruby/rake/blob/master/History.rdoc)
- [Commits](ruby/rake@v10.4.0...v13.0.1)

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

Author: dependabot-preview[bot]

line-bot-api.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency "addressable", "~> 2.3"
   spec.add_development_dependency "bundler", "~> 1.11" if RUBY_VERSION < "2.3"
-  spec.add_development_dependency 'rake', "~> 10.4"
+  spec.add_development_dependency 'rake', "~> 13.0"
   spec.add_development_dependency "rspec", "~> 3.0"
   spec.add_development_dependency "webmock", "~> 1.24"
 end