Merge pull request #48 from sensu-plugins/dependabot/bundler/bundler-tw-2.1

Update bundler requirement from ~> 1.7 to ~> 2.1

Author: Todd Campbell

.travis.yml

@@ -2,6 +2,8 @@ language: ruby
 services: docker
 cache:
 - bundler
+before_install:
+- gem install bundler
 install:
 - bundle install
 rvm:

sensu-plugins-filesystem-checks.gemspec

@@ -36,7 +36,7 @@ Gem::Specification.new do |s|
 
   s.add_runtime_dependency 'sensu-plugin', '~> 4.0'
 
-  s.add_development_dependency 'bundler',                   '~> 1.7'
+  s.add_development_dependency 'bundler',                   '~> 2.1'
   s.add_development_dependency 'codeclimate-test-reporter', '~> 0.4'
   s.add_development_dependency 'github-markup',             '~> 3.0'
   s.add_development_dependency 'pry',                       '~> 0.10'