Promote VolumeSubpathEnvExpansion to GA

[kevtaylor]

Is this a BUG REPORT or FEATURE REQUEST?:
/kind api-change
/sig storage
/sig node
/milestone v1.17

Description:
This is the issue that is used to upgrade VolumeSubpathEnvExpansion feature gate to GA.

Related Issues:
Beta Upgrade: #76546
Feature Request: kubernetes/enhancements#559
KEP: https://github.com/kubernetes/enhancements/blob/master/keps/sig-storage/20181029-volume-subpath-env-expansion.md

[k8s-ci-robot]

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In response to this:

Is this a BUG REPORT or FEATURE REQUEST?:
/kind api-change
/sig storage
/sig node
/milestone v1.17

Description:
This is the issue that is used to upgrade VolumeSubpathEnvExpansion feature gate to GA.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[kevtaylor]

/assign @kevtaylor
/cc @msau42

[neolit123]

please update kubernetes/enhancements#559 with the GA target.

[msau42]

Should we also consider adding the e2e tests to the conformance suite (as a separate pr)? cc @kubernetes/cncf-conformance-wg

[kevtaylor]

@msau42 Do you want me to put in a PR to switch the e2e tests to conformance level?
If so, just need some advice on that - seems like to just change It to ConformanceIt ?
Do we then need to leave the [sig-storage] tags - or remove them?
Any other additional tags that we need?

[johnbelamaric]

https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/conformance-tests.md

Please do that ASAP if you want it to make the release!

[johnbelamaric]

You can leave the sig-storage tags

[msau42]

sgtm!

[kevtaylor]

This has been released now, so closing