Move @types/quill to devDependencies to prevent clashes downstream

[jraoult]

@types/quill is declared as a regular dependencies, which means it is installed at the same time as quill-magic-url. It is then picked up by the Typescript compiler and clashes with any other @types/quill that the consumer would install. I actually encountered this when migrating to Quill v2 where the types are now bundle with the main package.

The solution would be to move @types/quill to devDependencies so it is not installed in downstream project.