chore: [#deps] Upgrade whatwg-mimetype to v5.0.0

[TrevorBurnham]

This PR upgrades whatwg-mimetype from v3 to v5. This is a routine dependency upgrade that should have no impact on behavior. The new package version is more modern and includes the TypeScript types, removing the need for the separate @types/whatwg-mimetype dep.

[ocavue]

In your PR description:

The new package version is more modern and includes the TypeScript types, removing the need for the separate @types/whatwg-mimetype dep.

But in your code:

// @ts-expect-error whatwg-mimetype v5 has no TypeScript declarations
import WhatwgMIMEType from 'whatwg-mimetype/lib/mime-type.js';

It seems that one of them is incorrect.

[TrevorBurnham]

🤦‍♂️ Sorry about that! I see that there's a pending PR to update the @types/whatwg-mimetype package for v5: DefinitelyTyped/DefinitelyTyped#74483 I'll update this PR to use those types once they're merged in.

[TrevorBurnham]

I've updated this PR to use both whatwg-mimetype@5.0.0 and the newly-minted @types/whatwg-mimetype@5.0.0.