📖 Add Cluster API release-1.12 timeline document

[mboersma]

What this PR does / why we need it:

This PR adds the release-1.12 cycle schedule document with preliminary dates.

/area release
/kind documentation

[sbueringer]

I'll let Fabrizio take a first look (he should be back soon)

/assign @fabriziopandini

[fabriziopandini]

@mboersma thanks for this! just a few small adjustments from my side

[mboersma]

/label tide/merge-method-squash

[sbueringer]

/assign

I'll also take a look ~ tomorrow

[sbueringer]

Thank you!
/lgtm

/assign @fabriziopandini
for a final look

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 7730e2dadec19af694c7da37c59ac10ca135249a

[mboersma]

Thanks for the help @fabriziopandini and @sbueringer. I incorporated all the feedback and rebased this.

[sbueringer]

One nit

[sbueringer]

/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: d30d62acf4f46a9e677703a692ca7fa9ca5f3284

[fabriziopandini]

Thanks @mboersma!
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fabriziopandini

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