create new experimental release

site-config/ymerge.py

-import yaml
 import sys
+from spack.config import merge_yaml, read_config_file, syaml
 
-with open(sys.argv[1], 'r') as f:
-  env = yaml.load(f, yaml.SafeLoader)
-with open(sys.argv[2], 'r') as f:
-  site_env = yaml.load(f, yaml.SafeLoader)
-
-for k in site_env['spack'].keys():
-  if k in env['spack'].keys():
-  	if isinstance(env['spack'][k], list): env['spack'][k].extend(site_env['spack'][k])
-  else: env['spack'][k] = site_env['spack'][k]
-
-yaml.dump(env, sys.stdout)
+print(syaml.dump(merge_yaml(read_config_file(sys.argv[1]), read_config_file(sys.argv[2]))))