Summary:
In [[https://svnweb.freebsd.org/ports?view=revision&revision=562203|r562203]]
and [[https://svnweb.freebsd.org/ports?view=revision&revision=562203|r562204]] the vuln.xml file was splitted by year.
As stated in the commit message, `pkg(8) audit` does not support entities and hence,
we need to use the vuln-flat.xml file to test changes to the port.
Test Plan:
* Try something like this:
```
$ pkg audit -f ./vuln.xml gitea-1.13.4
pkg: Syntax error while parsing vulnxml
pkg: cannot process vulnxml
```
and then:
```
$ pkg audit -f ./vuln-flat.xml gitea-1.13.4
0 problem(s) in 0 installed package(s) found.
```
After the patch:
* `igor` clean
* The documentation is rendered properly.
Reviewers: 0mp, gbe
Differential Revision: https://reviews.freebsd.org/D29219
bf79ecf9cf