Rename API Version v1beta1 to v1alpha5

[apricote]

/kind feature

Describe the solution you'd like

Rename the unreleased v1beta1 API Version to v1alpha5. There were some changes to the API that we should release at some point, but calling the API beta1 includes some guarantees about stability that we might not want to make right now.

By having an intermediate v1alpha5 we can get quickly get feedback on these changes and then create a new v1beta1 that is the same as v1alpha5 (or make any changes if that is needed).

Anything else you would like to add:

This was previously discussed in the Office Hours on 2022-03-23 with @mdbooth, @seanschneeweiss and @tobiasgiese.

[mkjpryor]

@apricote This sounds like exactly what alpha releases are for. There are a couple of features in the v1beta1 resources that I would like to try out so this would be a +1 from me.

[apricote]

/assign

[jichenjc]

+1 to me as we seems we are not that mature (yet)

[apricote]

/milestone v0.6