[DOCS] When generating Release Notes for a Release of Salt, include date

Description
Currently the doc's for release notes do not include a date which makes it hard to figure out when an old release occurred. Searching through salt-announce on Slack is not a good option, nor is relying on the date on the repository since this can change, for example: 3005.1 classic packages on the repository date, gives 2023-02-14, but it was built and released to test on Sept 30th 2022. So probably released early Oct 2022

Suggested Fix
When building release doc's insert date programmatically in International ISO format YYYY-MM-DD, which is an unchanging format understandable worldwide, it should NOT be in a regional format. While the date will be for when the release notes are generated and not when an actual release is made, the release notes are typically generated within a day or so of release, and will be close enough to give a close approximation as to when the release was made.

Type of documentation
Salt documentation

Location or format of documentation
for example https://docs.saltproject.io/en/latest/topics/releases/3005.1.html

Use the example release-note page at docs.saltproject.io/en/latest/topics/releases/3005.1.html as the output reference, then locate the code path that generates Salt release documentation. Verify how generated dates are obtained and formatted; done means release notes include an ISO YYYY-MM-DD generation date.