Drop MRI 2.3 support

.rubocop.yml

@@ -6,7 +6,7 @@ AllCops:
   DisplayCopNames: true
   DisplayStyleGuide: true
 
-  TargetRubyVersion: 2.3
+  TargetRubyVersion: 2.4
 
 Metrics:
   Enabled: false

.travis.yml

@@ -4,11 +4,9 @@ before_install:
   - gem update --system 3.0.3
   - gem install bundler:2.0.1
 rvm:
-  - 2.3.8
   - 2.4.5
   - 2.5.5
   - 2.6.2
-  - jruby-9.1.17.0
   - jruby-9.2.6.0
 branches:
   only:

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Master (unreleased)
 
+* Drop ruby 2.3 support. [#152][] by [@deivid-rodriguez][]
+
 ## 1.2.1 [☰](https://github.com/activeadmin/arbre/compare/v1.2.0...v1.2.1)
 
 * Revert [#64][] to fix several regressions, at the cost of reintroducing [#46][]. [#121][] by [@deivid-rodriguez][]
@@ -83,6 +85,7 @@ Initial release and extraction from Active Admin
 [#78]: https://github.com/activeadmin/arbre/pull/78
 [#110]: https://github.com/activeadmin/arbre/pull/110
 [#121]: https://github.com/activeadmin/arbre/pull/121
+[#152]: https://github.com/activeadmin/arbre/pull/152
 
 [@aramvisser]: https://github.com/aramvisser
 [@LTe]: https://github.com/LTe

arbre.gemspec

@@ -18,7 +18,7 @@ Gem::Specification.new do |s|
   s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
   s.require_paths = ["lib"]
 
-  s.required_ruby_version = '>= 2.3'
+  s.required_ruby_version = '>= 2.4'
 
   s.add_dependency("activesupport", ">= 3.0.0")
 end