fix(core): incorrect CloudFormation date formatting

[msambol]

The trailing Z is now required:

• ExpirationDate
• TransitionDate

Closes #28065, #28124.

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[lpizzinidev]

Looks good 👍
I left you a note on an added file.

Also, the dateToCloudFormation method is used when parsing dates for ScheduledAction's StartTime and EndTime.
Can you please add integration/unit tests for that as well?
(You can use this as a starting point).

Finally, I'm not sure about the title, it should describe the bug (not the solution).
Something like fix(core): wrong CloudFormation date formatting is probably more aligned.

[aws-cdk-automation]

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• CodeBuild project: AutoBuildv2Project1C6BFA3F-wQm2hXv2jqQv
• Commit ID: 3ff4bb8
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[msambol]

@lpizzinidev I updated the PR with the other integration test. 👍🏼

[lpizzinidev]

Thanks 👍

[SankyRed]

The change looks good to me. Thank you for your contribution.

[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).