schedule: add release schedule in yaml machine readable format

[cpanato]

What type of PR is this:

/kind documentation

What this PR does / why we need it:

Adds the schedule of the patch release in the YAML format to make it easier to machines read and parse.

Will open a second PR again k/release to add a small command-line tool to convert from YAML to markdown format to help to publish the schedule here

TODO:

• Add missing dates for the EOL for the existing releases.

Which issue(s) this PR fixes:

• Fixes machine readable release schedule #718

Special notes for your reviewer:

/cc @justaugustus @tpepper @kubernetes/release-managers

[cpanato]

/priority important-soon

[tpepper]

Did the parser not get a 'git add' before commit?

[cpanato]

@tpepper the parser Stephen suggest adding in the k/release

[cpanato]

@tpepper added the parser tool and update the schedule, just missing the EOL

[justaugustus]

@cpanato -- I left a review on the tool: kubernetes/release#1313 (review)

@kubernetes/release-engineering -- Let's review and merge that PR before merging this.
/hold

[cpanato]

@justaugustus thanks for the review, i will work to address the feedback!

[cpanato]

PR kubernetes/release#1313 was merged we can continue the review for this one here
cc @justaugustus for when you have some time thanks!

[tpepper]

@cpanato can you add some unit tests also for the tool?

[cpanato]

@tpepper yes, Tim, will add some tests

[cpanato]

@tpepper added some here: kubernetes/release#1349

[cpanato]

@tpepper @justaugustus PR to add the tool and PR for adding tests was merged.
we can proceed here

[cpanato]

@tpepper I know we all are busy and this is not a too high priority, but it is hanging for some time. All the things that you requested are already merged, missing this PR here only.

thanks!

[tpepper]

I'm ok merging this in its current state. I'd backed off on doing so since I wanted to see its lifecycle management documented, that got slotted behind Stephen's rewrite / unification of the branch and patch management role handbooks since it spans both roles and should just be in the one new doc, and that got stalled versus other things. I think multiple of us could do the doc update, but Stephen had a particular vision for how he wanted it done. Maybe if we can get that described we could help reduce his load if it's delegate-able.

/lgtm
/approve

[justaugustus]

I think the lifecycle of this can be documented outside of my deduplication and we can work it in to whichever final state we land on.

One ask: when documenting anything related to handling of this config, please do so in a separate markdown file instead of the existing handbook, so we don't have to worry about rebasing once I get time to sit down on this again.

Great work and sorry for the wait in merging!
/lgtm
/approve
/hold cancel

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cpanato, justaugustus, tpepper

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• releases/OWNERS [justaugustus,tpepper]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[cpanato]

thanks @tpepper @justaugustus lets try to sync what changes you all want and i can make that happen