Extension Name

n/a

Describe the bug

attempting to run the scripts will fail with

error converting template to map: yaml: unmarshal errors:
  line 0: mapping key "AWSToolsMetrics" already defined at line 4

looking at https://github.com/aws-cloudformation/rain/releases/tag/v1.21.0 , #627 looks to be the source of this issue.

downgrading to 1.20.1 fixes the issue for me

Expected behavior

scripts should work

Reproduction template

n/a