Allow negative lookahead for --regex-domain-exclusion

[MuriloCouceiro]

Hello,

In my use case, I'm trying to limit my external-dns to only create DNS records for specific hostnames that have one more level to the level of the Azure DNS Zone.

Example:
- DNS Zone: example.base.com
- Allowed records: app1.loc1.example.base.com, *.loc1.example.base.com
- Ignored records: any hostname that does not contain .loc1.example.base.com

I've tried with

 - --domain-filter= example.base.com
 - --regex-domain-exclusion=^(?!.*[a-zA-Z0-9-]+\.loc1).*$

but i get the following error

time="2024-01-05T17:14:13Z" level=fatal msg="flag parsing error: error parsing regexp: invalid or unsupported Perl syntax: (?!"

Is this possible?

Thank you in advance!