Change explicit v1_28 feature to use latest feature alias

[clux]

Simplify our build setup to always set our MAX as the latest version k8s-openapi exposes.

This doesn't let us avoid all the automation to bump (still need an explicit version for k3d on CI for the minimum check), but it avoids having to bump all the readme and toml files for the latest dev-deps.

Brought up in #1291 (comment)

Have updated recommendations in https://kube.rs/kubernetes-version/ to more explicitly tell users to use latest unless they have a reason for it (before we where a bit vague about it - but now it's easier with the feature alias).

[codecov]

Codecov Report

Merging #1292 (c4441bb) into main (044cac4) will decrease coverage by 0.02%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1292      +/-   ##
==========================================
- Coverage   72.31%   72.30%   -0.02%     
==========================================
  Files          75       75              
  Lines        6347     6347              
==========================================
- Hits         4590     4589       -1     
- Misses       1757     1758       +1     

see 1 file with indirect coverage changes