remove hardcoded require

[tsnobip]

The hardcoded require would sometimes not play well with bundling and the esmodule mode of rescript.

When using esmodule mode, it should now generate an import instead of a require:

import * as React from "react";

[mununki]

Good catch! I'm just looking for any other way to avoid the removing the unused value by the compiler's optimization without making an unnecessary applying.

[mununki]

Unfortunately, I haven't found a way to avoid creating unnecessary values with a compiler feature. Sorry for the delayed review.

[tsnobip]

I tried many things too but couldn't come up with a better solution either!

[tsnobip]

@mununki sorry I forgot to update the changelog, can you approve the PR again?