Update objects and tests for client 18.x.x

[mindw]

This seems like a major backwards compatibility change. Not sure how to prevent that.

Fixes #217

Some observations:

1. The requirements of kubetest are far wider than the ones tested. This seems to be the root cause of why this issue doesn't show up in tests but affects users. Perhaps making the setup.py ones a little more restrictive while the tests looser?
2. It may be useful to change the versioning scheme to match the k8s python client one - it would at least help users to understand which version of kubetest matches the k8s client.

Thank you for investing time an effort into great project :)

[mindw]

Not sure why CI fails - unable to reproduce locally:

                                                                                                                                                                                                                                                                                 
Gabi Davar@GABI-PC J:\dev\src\kubetest                                                                                                                                                                                                                                           
# .tox\py310\Scripts\coverage run --parallel --source kubetest -m pytest -s tests                                                                                                                                                                                                
============================================================================================================================== test session starts ==============================================================================================================================
platform win32 -- Python 3.10.0, pytest-6.2.5, py-1.10.0, pluggy-1.0.0                                                                                                                                                                                                           
kubetest config file: default                                                                                                                                                                                                                                                    
kubetest context: current context                                                                                                                                                                                                                                                
rootdir: J:\dev\src\kubetest                                                                                                                                                                                                                                                     
plugins: kubetest-0.9.5                                                                                                                                                                                                                                                          
collected 115 items                                                                                                                                                                                                                                                              
                                                                                                                                                                                                                                                                                 
tests\test_conditions.py ....................................                                                                                                                                                                                                                    
tests\test_manager.py .....                                                                                                                                                                                                                                                      
tests\test_manifest.py .....................................................                                                                                                                                                                                                     
tests\test_utils.py ...............                                                                                                                                                                                                                                              
tests\objects\test_api_object.py ......                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                 
============================================================================================================================== 115 passed in 0.75s ==============================================================================================================================
                                                                                                                                                                                                                                                                                 ```

[disrupted]

looks good to me, could you request a review from the maintainers?

[mindw]

@edaniszewski can a few cycles be spared for reviewing this PR? Tx!

[vladciobancai]

Hi, are there any chances for this PR to be merged?