Update sensu-plugins to ~> 2.7, which includes breaking changes

Closes #10.
The occurrences filtering was removed from sensu-plugin and moved into a
Sensu extension (https://github.com/sensu/sensu-extensions-occurrences).
The example configuration has been updated.

Author: lagartoflojo

CHANGELOG.md

@@ -4,8 +4,13 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 This CHANGELOG follows [this format](https://github.com/sensu-plugins/community/blob/master/HOW_WE_CHANGELOG.md).
 
 ## [Unreleased]
+
+## [3.0.0] - 2018-11-24
 ### Breaking Changes
 - Remove support for Ruby < 2.3 per the Sensu Plugins [policy](https://github.com/sensu/sensu-docs/blob/master/content/plugins/1.0/faq.md#what-is-the-policy-on-supporting-end-of-lifeeol-ruby-versions).
+- Update sensu-plugins to `~> 2.7`. Many breaking changes, see:
+  - [1.4.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#v140---2016-07-20)
+  - [2.0.0](https://github.com/sensu-plugins/sensu-plugin/blob/master/CHANGELOG.md#v200---2017-03-29)
 
 ### Security
 - Updated Rubocop to `~> 0.60.0`, which fixes [CVE-2017-8418](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-8418).

README.md

@@ -19,7 +19,8 @@ After installation, you have to set up a `pipe` type handler, like so:
   "handlers": {
     "telegram": {
       "type": "pipe",
-      "command": "handler-telegram.rb"
+      "command": "handler-telegram.rb",
+      "filter": "occurrences"
     }
   }
 }

lib/sensu-plugins-telegram/version.rb

@@ -2,9 +2,9 @@
 
 module SensuPluginsTelegram
   module Version
-    MAJOR = 2
+    MAJOR = 3
     MINOR = 0
-    PATCH = 1
+    PATCH = 0
 
     VER_STRING = [MAJOR, MINOR, PATCH].compact.join('.')
   end

sensu-plugins-telegram.gemspec

@@ -37,8 +37,8 @@ Gem::Specification.new do |s| # rubocop:disable Metrics/BlockLength
   s.test_files             = s.files.grep(%r{^(test|spec|features)/})
   s.version                = SensuPluginsTelegram::Version::VER_STRING
 
-  s.add_runtime_dependency 'sensu-plugin', '~> 1.1'
   s.add_runtime_dependency 'rest-client',  '~> 2.0'
+  s.add_runtime_dependency 'sensu-plugin', '~> 2.7'
 
   s.add_development_dependency 'bundler',                   '~> 1.7'
   s.add_development_dependency 'codeclimate-test-reporter', '~> 0.4'