chore: Lower the min Ruby version to 2.7.

Author: schwern

.rubocop.yml

@@ -5,7 +5,7 @@ require:
 
 AllCops:
   NewCops: enable
-  TargetRubyVersion: 3.0
+  TargetRubyVersion: 2.7
 
 # Useful to separate conceptual expressions.
 Layout/SpaceInsideArrayLiteralBrackets:

time_range.gemspec

@@ -11,7 +11,7 @@ Gem::Specification.new do |spec|
   spec.summary = "Iterate using Time objects."
   spec.description = "Easy iterating over various periods of time."
   spec.homepage = "https://github.com/schwern/ruby-time_range"
-  spec.required_ruby_version = "~> 3.0"
+  spec.required_ruby_version = ">= 2.7"
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = "https://github.com/schwern/ruby-time_range"