Fix Travis CI builds (#30)

* Bump allowed bundler version
* Drop support for Ruby 2.1

.travis.yml

@@ -5,26 +5,26 @@ env:
 language: ruby
 
 rvm:
-  - 2.1
   - 2.2
   - 2.3
   - 2.4
   - 2.5
+  - 2.6
 
 before_install:
   - gem update bundler
 
 install:
   - bundle install --jobs=3 --retry=3
-  - if [[ ! `ruby --version` =~ ^ruby\ 2\.1 ]]; then gem install rubocop; fi
+  - gem install rubocop
 
 before_script:
   - curl -L https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64 > ./cc-test-reporter
   - chmod +x ./cc-test-reporter
   - ./cc-test-reporter before-build
 
 script:
-  - if [[ ! `ruby --version` =~ ^ruby\ 2\.1 ]]; then rubocop; fi
+  - rubocop
   - bundle exec rake
 
 after_script:

rocketchat.gemspec

@@ -18,11 +18,11 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.add_development_dependency 'bundler', '~> 1.11'
+  spec.add_development_dependency 'bundler', ['>= 1.11', '< 3.0']
   spec.add_development_dependency 'rake', '~> 10.0'
   spec.add_development_dependency 'rspec', '~> 3.0'
-  spec.add_development_dependency 'rubocop', '~> 0.57'
-  spec.add_development_dependency 'rubocop-rspec', '~> 1.27'
+  spec.add_development_dependency 'rubocop', '~> 0.62'
+  spec.add_development_dependency 'rubocop-rspec', '~> 1.31'
   spec.add_development_dependency 'simplecov', '~> 0.16'
   spec.add_development_dependency 'webmock', '~> 2.3'
   spec.add_development_dependency 'yard', '~> 0.9.11'