Allow substitution of "{date}" in @author tag.

[helixquar]

Feature

• [x] Description of what's added

In addition to {author} and {email}, this PR adds {date} to the @author tag.

• [ ] Added gif to README

• [ ] Added unit test

[helixquar]

@cschlosser, would you welcome PRs for very specific use cases like this?

I needed something like:

@author NAME 2022/12/22 Description

But I don't think there's a lot of people who will be using it this way.

Do you think it would be better if I generalize this change to making all substitutions work for all tags?

[cschlosser]

Hi @helixquar ,

It's fine as is. Please just also address the other two checkboxes and then I will merge it.