relax requirement on exact version of simplejson

[thomasdziedzic-calmwave]

This strict requirement makes it impossible to bump simplejson to another major version of simplejson like 3.19.
Is there a reason why this is pinned on an exact minor version of simplejson rather than using something like >= 3.18.4?

relevant file https://github.com/aws/aws-lambda-python-runtime-interface-client/blob/main/requirements/base.txt

[PartiallyUntyped]

Hi,
Afaik this will be relaxed once we migrate to a more modern way to manage the package via pyproject.toml. This is in the works.