Runner versioning policy

[roman-khimov]

Is your feature request related to a problem? Please describe.

I'm always frustrated when we're talking about ubuntu-20.04/ubuntu-22.04/ubuntu-24.04 runners vs ubuntu-latest. We use ubuntu-based runners a lot and either we stick to some specific version and upgrade it from time to time or we're trusting the latest to be OK. Right now we do both, some places have fixed version, some latest. This leads to confusion.

Describe the solution you'd like

Establish some policy wrt this.

Describe alternatives you've considered

Don't worry about it.

Additional context

Just about any version update brings this discussion again and again, like nspcc-dev/rfc6979#10 (comment).

[smallhive]

Using latest makes sense and it should be used by default. If some case requires a specified version, it should be done in place with a comment

[AnnaShaleva]

Latest version has one drawback: we can’t control runner upgrades which may lead to unexpected job failures when runner version is updated. But these failures not hard to detect/investigate.

Using specific version requires its manual update, and it’s the thing that we should always remember. It’s kind of a drawback to me, and thus I vote for the latest version.

[EESergey]

If something important might stop working due to a version update, we need to test the new versions. If we are running tests before applying changes, we should use the latest version.