TTL can not be set (not a number)

[darioackermann]

When supplying a TTL value, stack creation will fail with Received response status [FAILED] from custom resource. Message returned: invalid resource properties: '60' is not of type 'number

This probably happens because when using a custom resource, the parameters are sent as string, however the custom resource is enforcing it to be a number type

https://github.com/binxio/cfn-cross-account-dns-provider/blob/main/src/cfn_cross_account_dns_provider/cross_account_dns.py#L30

It neither works when using a Parameter with Type Number and then referring to it via !Ref TTL.