Unrecognized property 'ownershipControls'

Hi,

I am trying to modify one of the buckets that is attached to the lambda function that my serverless.yml deploys. I am trying to configure the object ownership to be “BucketOwnerPreferred”. Referencing AWS documentation ( AWS::S3::Bucket OwnershipControls - AWS CloudFormation (amazon.com)) I would use the variable “ownershipControls” (lowercase o because I am modifying the property inline and not in the ‘resources’ section).

However, this variable is not recognized. Am I calling it wrong here? Code block is as follows:

provider:
  stage: dev
  name: aws
  profile: ${self:custom.useProfile}
  runtime: nodejs14.x
  s3:
    publicBucket:
      name: ${self:custom.publicBucket}
      publicAccessBlockConfiguration:
        BlockPublicAcls: false
        BlockPublicPolicy: false
        RestrictPublicBuckets: false
      ownershipControls:
          Rules:
            - ObjectOwnership: BucketOwnerEnforced

Any help is greatly appreciated!!

Thank you,
Donny