Updating sensu-plugin version & removing Ruby 2.1 & 2.2

.travis.yml

@@ -4,9 +4,6 @@ cache:
 install:
 - bundle install
 rvm:
-- 2.0
-- 2.1
-- 2.2
 - 2.3.0
 - 2.4.1
 notifications:
@@ -27,9 +24,6 @@ deploy:
   on:
     tags: true
     all_branches: true
-    rvm: 2.0
-    rvm: 2.1
-    rvm: 2.2
     rvm: 2.3.0
     rvm: 2.4.1
     repo: sensu-plugins/sensu-plugins-mailer

CHANGELOG.md

@@ -5,6 +5,10 @@ This CHANGELOG follows the format listed [here](https://github.com/sensu-plugins
 
 ## [Unreleased]
 
+### Breaking Changes
+- Bump sensu-plugin version from `~> 2.0` to `~> 4.0` for Sensu 1.x to Sensu Go event conversion you can read the changelog entries for [4.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#400---2018-02-17) and [3.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#300---2018-12-04)
+- drop support and testing for ruby 2.1 and 2.2 as they are EOL
+
 ## [3.0.0] - 2018-12-07
 ### Breaking Changes
 - bumped dependency of `sensu-plugin` to 2.x you can read about it [here](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#v145---2017-03-07) (@asachs01)

sensu-plugins-mailer.gemspec

@@ -22,15 +22,15 @@ Gem::Specification.new do |s|
   s.platform               = Gem::Platform::RUBY
   s.post_install_message   = 'You can use the embedded Ruby by setting EMBEDDED_RUBY=true in /etc/default/sensu'
   s.require_paths          = ['lib']
-  s.required_ruby_version  = '>= 2.0.0'
+  s.required_ruby_version  = '>= 2.3.0'
   s.summary                = 'Sensu plugins for mailer'
   s.test_files             = s.files.grep(%r{^(test|spec|features)/})
   s.version                = SensuPluginsMailer::Version::VER_STRING
 
   s.add_runtime_dependency 'aws-ses',           '0.6.0'
   s.add_runtime_dependency 'mail',              '2.6.3'
   s.add_runtime_dependency 'mailgun-ruby',      '1.0.3'
-  s.add_runtime_dependency 'sensu-plugin',      '~> 2.7'
+  s.add_runtime_dependency 'sensu-plugin',      '~> 4.0'
   s.add_runtime_dependency 'erubis',            '2.7.0'
   s.add_runtime_dependency 'ruby-ntlm',         '0.0.3'