Add MIT license

[nnmrts]

Hello!

I noticed this repository doesn't have a license. Of course there is ISC in the package.json license field, but I don't think that's intentional as it's just the default option when running npm init and I'm also not sure it's sufficient. I looked through some of your (@gvergnaud) other repositories and it seems like you prefer the MIT license, so I chose it here.

You may not be aware of this, but legally, without a license, no one can use your code.

https://choosealicense.com/no-permission/

[nnmrts]

Since this repository also has some contributors, I'm fairly certain they have to give permission to a full license addition/change. Sorry for pinging you guys but AFAIK this PR can't move forward without your approval.

@ecyrbe @frankie303 @sno2 @un4uthorized @Beraliv @eloytoro @ggrandi @adamsuskin @AeRo8 @jessekelly881

[Beraliv]

@nnmrts @Sardonyx001 I only contributed a small number of features, therefore it's not up to me to decide on the license. If it comes back to me, I'm happy to make it MIT or a more secure license

Based on number of contributions, the decision comes to @gvergnaud and @ecyrbe

[jessekelly881]

a-ok with me :) (just seeing this now)

[ggrandi]

That is fine by me

[gvergnaud]

Hey, the MIT license file was added on the main branch. Closing this PR