[DOC] faq about eol images

[sozercan]

What kind of documentation improvement is needed?

Missing information or guidance

What is the change that is needed?

We should document that copa will not be able to patch images that are EOL and OS vendors have taken down the package repositories.

Example: kedacore/keda-metrics-apiserver:2.0.0-beta

Output:

#4 0.424 Ign:1 http://security.debian.org/debian-security stretch/updates InRelease
#4 0.429 Err:2 http://security.debian.org/debian-security stretch/updates Release
#4 0.429   404  Not Found
#4 0.738 Ign:3 http://deb.debian.org/debian stretch InRelease
#4 0.901 Ign:4 http://deb.debian.org/debian stretch-updates InRelease
#4 1.064 Err:5 http://deb.debian.org/debian stretch Release
#4 1.064   404  Not Found
#4 1.228 Err:6 http://deb.debian.org/debian stretch-updates Release
#4 1.228   404  Not Found

Are you willing to submit PRs to contribute to documentation?

• [ ] Yes, I am willing to implement it.