Allow to change extension of cjs and mjs files

[prisis]

Clear and concise description of the problem

I want to have the possibility to change the file ending of the cjs and mjs files

Suggested solution

Add a option to the packem.config with the extension to overwrite what extensions should be used on package.json
Use the provided extension in the package.json

Alternative

No response

Additional context

No response

Validations

• Follow our Code of Conduct.
• Read the Contributing Guidelines.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[prisis]

Will be worked on in #105