Update development dependencies to solve error

Author: andyw8

readwise.gemspec

@@ -37,8 +37,8 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_development_dependency "bundler", "~> 2.2"
-  spec.add_development_dependency "rake", "~> 10.0"
+  spec.add_development_dependency "bundler", "~> 2.6"
+  spec.add_development_dependency "rake", "~> 13.0"
   spec.add_development_dependency "rspec", "~> 3.0"
   spec.add_development_dependency "rspec-file_fixtures", "~> 0.1.6"
 end