docs: define linter deprecation cycle

[ldez]

I feel like we agree on my proposal, and then I propose to explain it in the documentation.

Fixes #1987

[bombsimon]

We could, given that the new plugin system lands, write a note about that. Because people will get upset because their favorite linter that works great with Go 1.13 now is gone! We can then add a note saying that the consumer of the linter can implement that exact linter as a plugin and keep using it.

We don't have to go into detail, just saying that it's possible and link to those parts of the docs.

[ldez]

We could, given that the new plugin system lands, write a note about that.

I agree.
For now, the PR about the new plugin system is not merged, I don't know if I have to wait again.
If there is no feedback by tomorrow, on PR about plugins, then I will merge it and add a link to the deprecation section inside this PR.

[alexandear]

LGTM

[ldez]

We can then add a note saying that the consumer of the linter can implement that exact linter as a plugin and keep using it.

After more thinking, we can't recommend/suggest using a plugin for a deprecated linter.

The linter needs to be modified, but if it is archived it will not be possible.

And if the linter doesn't work with the current Go version, it will not work, even as a plugin, even with an older version of Go, because our code base also depends on a minimal Go version.

Talking about plugins in this section will be confusing.

[Antonboom]

👍