Support multiple CRD versions

[whentojump]

Description

If the supplied CRD contains multiple versions, Acto will always pick up the first one during --learn stage:

acto/acto/utils/preprocess.py

Line 143 in 92fb7c3

"version": spec.versions[0].name,

If the intended or latest version isn't the head of the list, Acto will use the wrong one.

Specifically, for percona/percona-server-mongodb-operator, in its bundle.yaml of v1.15.0, a deprecated version (v1-2-0) is put under path spec.versions[0], and the version we want (v1) is put under path spec.versions[11]. Learning phase would fail because accessing https://host:port/apis/psmdb.percona.com/v1-2-0/... returns 404.

(Incidentally, for the old in-tree bundle.yaml, Acto also selected the first version (v1alpha1, see context.json) instead of the last one (v1-12-0). But somehow that config worked fine.)

Solutions

1. Allow user to specify version in config.json
2. Pick up the version more smartly (But this seems harder if the version scheme is ad-hoc per project)
3. Before 1 or 2 is implemented, in relevant documentation, like here and here, we'd better put a notice that we should remove preceding unwanted versions and put the intended one first.