docs: add the MIT license

[Panquesito7]

Fixes Issue

Closes #59.

Changes proposed

• Add the MIT license.

Check List (Check all the applicable boxes)

• [x] My code follows the code style of this project.
• [ ] My change requires changes to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] All new and existing tests passed.
• [x] This PR does not contain plagiarized content.
• [x] The title of my pull request is a short description of the requested changes.