Doctype Definition in cert-data

Ahoi!

I had a look at /var/lib/openvas/cert-data/dfn-cert-[YYYY].xml and found a reference to a doctype definition at DFN’s website:
http://www.dfn-cert.de/dfncert.dtd
This link is forwarded to https://www.dfn-cert.de/dfncert.dtd that does not exist.
This information tag is not used by the software and therefore this error does not affect the function, but I justed wanted to note that.

Cheers