Install python 3.9 for al2

Author: hgreebe

cookbooks/aws-parallelcluster-shared/attributes/versions.rb

@@ -4,6 +4,9 @@
   default['cluster']['python-version'] = '3.9.20'
 end
 default['cluster']['python-major-minor-version'] = '3.12'
+if platform?('amazon') && node['platform_version'] == "2"
+  default['cluster']['python-major-minor-version'] = '3.9'
+end
 
 # ParallelCluster versions
 default['cluster']['parallelcluster-version'] = '3.13.0'