Build versioned native extension paths for Ruby 3.2-4.0

Install the compiled extension into lib/code_ownership/<major.minor>/ so cross-gem
can package multiple Ruby minors into a single platform gem without overwriting.

Author: joemsak

.gitignore

@@ -9,6 +9,9 @@
 /target/
 /vendor
 
+# Locally-built native extensions (installed into versioned directories)
+/lib/code_ownership/*/
+
 Gemfile.lock
 
 # rspec failure tracking

code_ownership.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
           'public gem pushes.'
   end
 
-  spec.required_ruby_version = '>= 3.2'
+  spec.required_ruby_version = Gem::Requirement.new('>= 3.2', '< 5')
 
   # https://guides.rubygems.org/make-your-own-gem/#adding-an-executable
   # and

ext/code_ownership/extconf.rb

@@ -3,7 +3,8 @@
 require 'mkmf'
 require 'rb_sys/mkmf'
 
-create_rust_makefile('code_ownership/code_ownership') do |ext|
+ruby_minor = RUBY_VERSION[/\d+\.\d+/]
+create_rust_makefile("code_ownership/#{ruby_minor}/code_ownership") do |ext|
   ext.extra_cargo_args += ['--crate-type', 'cdylib']
   ext.extra_cargo_args += ['--package', 'code_ownership']
 end

rakelib/compile.rake

@@ -1,5 +1,6 @@
 require 'rb_sys/extensiontask'
 
 RbSys::ExtensionTask.new('code_ownership', GEMSPEC) do |ext|
-  ext.lib_dir = 'lib/code_ownership'
+  ruby_minor = RUBY_VERSION[/\d+\.\d+/]
+  ext.lib_dir = "lib/code_ownership/#{ruby_minor}"
 end