package-list is not present for javadocs

[solonovamax]

The package-list file is not present for many of the javadocs hosted at https://www.slf4j.org/.

It's also not present for the following urls:

• https://www.slf4j.org/api/
• https://www.slf4j.org/apidocs/
• https://www.slf4j.org/apidocs-2.1.0/
• https://www.slf4j.org/apidocs-2.1.0-alpha0/

it is however present on the following urls:

• https://www.slf4j.org/testapidocs/
• https://www.slf4j.org/nlog4j/api/

This is an issue for me, as I'm trying to add slf4j as an external link to dokka, and is attempting to resolve the package-list file.