Update to a currently supported ruby version: 2.6.6

Author: ikatz-drizly

.ruby-version

@@ -0,0 +1 @@
+2.6.6

.travis.yml

@@ -1,8 +1,8 @@
 sudo: false
 language: ruby
 rvm:
-- 2.2.4
-before_install: gem install bundler -v 1.13.3
+- 2.6.6
+before_install: gem install bundler -v 2.1.4
 after_success: bundle exec codeclimate-test-reporter
 env:
   matrix:

aws-rotate-keys.gemspec

@@ -23,7 +23,7 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "aws-sdk", "~> 2"
 
-  spec.add_development_dependency "bundler", "~> 1.13"
+  spec.add_development_dependency "bundler", "~> 2.0"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", "~> 3.0"
   spec.add_development_dependency "simplecov"