Fix MissingDynamic error

[mo-lucy-gordon]

After recent updates, 3 errors appeared when installing stylist with pip install .

Upon initial testing, the first solution suggested by the error messages did eliminate the errors; I added the 3 values, mentioned in the error messages, to this line in pyproject.toml :
dynamic = ['version', 'authors', 'keywords','readme']

More Details to reproduce the error yourself:

When installing a branch of stylist with editable mode: pip install stylist -e . , I came across the following error for 3 values in pyproject.toml file:

The following seems to be defined outside of "pyproject.toml":
      
              "authors = Met Office"

According to the spec (see the link below), however, setuptools CANNOT consider this value unless "readme" is listed as "dynamic".

https://packaging.python.org/en/latest/specifications/declaring-project-metadata/
      
To prevent this problem, you can list `authors` under `dynamic` or alternatively
remove the `[project]` table from your file and rely entirely on other means of
configuration.