Add PCLUSTER_PYTHON_ROOT to event handler environment

PCLUSTER_PYTHON_ROOT points to the bin folder of the python installation for the event handler, e.g.
`/home/pcluster-scheduler-plugin/.pyenv/versions/3.9.9/envs/scheduler_plugin_virtualenv/bin`

Signed-off-by: Luca Carrogu <[email protected]>

Author: lukeseawalker

cookbooks/aws-parallelcluster-scheduler-plugin/resources/execute_event_handler.rb

@@ -185,6 +185,9 @@ def build_static_env(target_cluster_config, target_launch_templates, target_inst
     # PCLUSTER_HEADNODE_HOSTNAME
     env.merge!(build_hash_from_node('PCLUSTER_HEADNODE_HOSTNAME', true, :hostname))
 
+    # PCLUSTER_PYTHON_ROOT
+    env.merge!({ 'PCLUSTER_PYTHON_ROOT' => "#{node['cluster']['scheduler_plugin']['virtualenv_path']}/bin" })
+
     # PCLUSTER_CLUSTER_CONFIG_OLD
     # TODO: to be implemented