feat,chore,doc: Add support for ruby 3.0

- enable travis tests on ruby 3.0
- update README file
- update rspec-json_expectations version requirements to one that works also on ruby 3.0

.travis.yml

@@ -2,6 +2,7 @@ sudo: false
 language: ruby
 rvm:
 - jruby
+- 3.0
 - 2.7
 - 2.6
 - 2.5

README.md

@@ -10,6 +10,7 @@ Leverage the [Unleash Server](https://github.com/Unleash/unleash) for powerful f
 
 ## Supported Ruby Interpreters
 
+  * MRI 3.0
   * MRI 2.7
   * MRI 2.6
   * MRI 2.5

unleash-client.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "bundler", "~> 2.1"
   spec.add_development_dependency "rake", "~> 12.3"
   spec.add_development_dependency "rspec", "~> 3.9"
-  spec.add_development_dependency "rspec-json_expectations", "~> 2.1"
+  spec.add_development_dependency "rspec-json_expectations", "~> 2.2"
   spec.add_development_dependency "webmock", "~> 3.8"
 
   spec.add_development_dependency "coveralls", "~> 0.8"