Update yum config for CentOS Stream 9 (#172)

The Powertools repo doesn't exist for CentOS Stream 9.  The equivalent
packages are in the CRB repo.

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- CentOS Stream 9 uses 'crb' instead of the 'powertools' repo.
+
 ## 2.5.5 - *2023-10-26*
 
 ## 2.5.4 - *2023-09-29*

resources/install.rb

@@ -10,7 +10,13 @@
   src_path = "#{Chef::Config['file_cache_path']}/ruby-build"
 
   if platform_family?('rhel')
-    if node['platform_version'].to_i >= 8
+    if node['platform_version'].to_i == 9
+      package 'yum-utils'
+
+      execute 'yum-config-manager --enable crb' do
+        not_if 'yum-config-manager --dump crb | grep -q "enabled = 1"'
+      end
+    elsif node['platform_version'].to_i == 8
       package 'yum-utils'
 
       execute 'yum-config-manager --enable powertools' do