Improvements to GitHub Projects (beta)

[Disper]

Description
After write access to kyma-project/kyma was revoked due to implementation of kyma-project/community#613, GitHub projects (beta) boards became much less useful.

Reasons

• GitHub Projects (beta) UI is a convenient tool to be used to navigate and edit issues that's no longer usable in a same way since write access has been revoked.
• Fields edited via GitHub projects are autocompleted and you don't need to spend time in searching e.g. for the right label name.

Acceptance Criteria

• User is able to change assignees from project's list-view
• User is able to change labels from project's list-view
• User is able to change milestones from project's list-view
• User should still be able to change any custom field that was added for the board from project's list-view
• All above should work for both Issues and Drafts

[Disper]

/area tooling

[arturskorupa]

/area xyz

[kyma-bot]

@arturskorupa: The label(s) area/xyz cannot be applied, because the repository doesn't have them.

In response to this:

/area xyz

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.

[kasiakepka]

Closing due to #5492