chore: migrate to react 18

[martimalek]

What:

Migrate to react 18

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Why:

We want to stop supporting react<18 in Wave 2.0 (#239)
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How:

• Bump react and react-dom versions to ^18.2.0 (not sure if we should target ^18.0.0 instead)
• Use react's useId instead of the internal generateId in useGeneratedId

Checklist:

• Fix type errors
• Use react's useId in Month.tsx instead of the internal generateId
• Remove our internal util generateId once it's no longer used
• Remove nanoid dependency
• Remove IE11 polyfill required for nanoid once it's no longer used (basically remove polyfills.ts)
• Fix dependency errors (docz is not compatible with React 18)
• Ready to be merged

Since we already refactored useGeneratedId to not use nanoid I think it makes sense to finish removing nanoid in this PR, that would mean that #240 is a duplicate, I'm keeping it alive for now to hear other's opinions

[martimalek]

I'm closing this since I was using a fork and now I've opened the PR directly from the branch of this repo in #311