Use the tag date as the release date

[sleberknight]

Instead of using the date/time that the change log is generated as the release date, we should use the data the (annotated) tag was created. This will be useful if you release software, but don't create the release in GitHub immediately. For example, this happened recently in kiwi-js when 0.12.0 was released but (due to a temporary problem with GitHub not setting headers correctly), the release on GitHub was not until several days later.

This will need to make a REST call to get the release tag using the REST API endpoints for Git tags

Unfortunately, we will need to make two requests:

1. Get the tag reference information
2. Use the object URL in the first response to get the tag SHA and from that, get the annotated tag details

For example, GET https://api.github.com/repos/kiwiproject/kiwiproject-changelog/git/matching-refs/tags/v1.0.1 returns:

[
    {
        "ref": "refs/tags/v1.0.1",
        "node_id": "MDM6UmVmMzMyMDY3ODY0OnJlZnMvdGFncy92MS4wLjE=",
        "url": "https://api.github.com/repos/kiwiproject/kiwiproject-changelog/git/refs/tags/v1.0.1",
        "object": {
            "sha": "e6be73f6bad45cffac32bd8f633ec6125b729b0b",
            "type": "tag",
            "url": "https://api.github.com/repos/kiwiproject/kiwiproject-changelog/git/tags/e6be73f6bad45cffac32bd8f633ec6125b729b0b"
        }
    }
]

You then make a request to the object.url to get the annotated tag information

So, from the above you would make a GET https://api.github.com/repos/kiwiproject/kiwiproject-changelog/git/tags/e6be73f6bad45cffac32bd8f633ec6125b729b0b which returns:

{
    "node_id": "TA_kwDOE8r0GNoAKGU2YmU3M2Y2YmFkNDVjZmZhYzMyYmQ4ZjYzM2VjNjEyNWI3MjliMGI",
    "sha": "e6be73f6bad45cffac32bd8f633ec6125b729b0b",
    "url": "https://api.github.com/repos/kiwiproject/kiwiproject-changelog/git/tags/e6be73f6bad45cffac32bd8f633ec6125b729b0b",
    "tagger": {
        "name": "Scott Leberknight",
        "email": "174812+sleberknight@users.noreply.github.com",
        "date": "2024-09-02T17:38:24Z"
    },
    "object": {
        "sha": "7da1a3dfbdc2d8ac65436d8ccae4d100bbef08df",
        "type": "commit",
        "url": "https://api.github.com/repos/kiwiproject/kiwiproject-changelog/git/commits/7da1a3dfbdc2d8ac65436d8ccae4d100bbef08df"
    },
    "tag": "v1.0.1",
    "message": "[maven-release-plugin] copy for tag v1.0.1\n",
    "verification": {
        "verified": false,
        "reason": "unsigned",
        "signature": null,
        "payload": null
    }
}

This second response contains the date in the tagger object of the annotated tag.

If we fail to get a date, for example if the tag is not an annotated tag, then we should log a warning and fall back to the way it works now, basically the time the change log is generated.