Bump the required ruby_version to 2.4.0

Author: byroot

.rubocop.yml

@@ -1,5 +1,5 @@
 AllCops:
-  TargetRubyVersion: 2.3
+  TargetRubyVersion: 2.4
 
 Layout/LineLength:
   Max: 120
@@ -100,7 +100,7 @@ Style/WordArray:
 Lint/NonLocalExitFromIterator:
   Enabled: false
 
-Lint/EndAlignment:
+Layout/EndAlignment:
   EnforcedStyleAlignWith: variable
 
 Layout/ElseAlignment:

redis.gemspec

@@ -43,7 +43,7 @@ Gem::Specification.new do |s|
   s.files         = Dir["CHANGELOG.md", "LICENSE", "README.md", "lib/**/*"]
   s.executables   = `git ls-files -- exe/*`.split("\n").map { |f| File.basename(f) }
 
-  s.required_ruby_version = '>= 2.3.0'
+  s.required_ruby_version = '>= 2.4.0'
 
   s.add_development_dependency("em-synchrony")
   s.add_development_dependency("hiredis")