Avoid fixed date in template

[hturner]

Comment from @ajrgodfrey

The template article includes a fixed date in the YAML date: "2022-11-09". It would be better to set the date programmatically, i.e. date: "r Sys.Date()"

I guess the fixed date is when the template was last updated, but this does not encourage good practice. Maybe the date of last update could be included in the main text instead.

[mitchelloharawild]

This should be added to the submission checks - checking that the article's date matches the current date when they submit the article.

Using a dynamic date will be problematic for our issue rendering process.