[FEATURE] Pattern (regex) Demo

[GuillaumeFalourd]

What would you like to be added:

A formula demonstration showing how to use the pattern (regex) opcional fields on the config.json formula file.

More informations here: https://docs.ritchiecli.io/tutorials/formulas/how-to-implement-a-formula/config-file

Obs: The documentation will redirect to the formula's readme afterwards.

Why is this needed:

To give an example to Ritchie users.