Fix 678 bimap resolving async left

[perfectmak]

This implements a fix for bimap to await reject promises returned by the left mapping functions.

Currently, the following code:

async function runBimap() {
    EitherAsync(async ({ throwE }) => {
        throwE(new Error("error"))
    })
    .bimap(asyncMapFn, asyncMapFn)
    .caseOf({
        Left: (error) => {
            console.log({ error })
        },
        Right: (value) => {
            console.log({ value })
        },
    })

}

await runBimap()

Will output:

Object {error: Promise (resolved)}

This PR fixes it, so that it outputs:

Object {error: Error: error}

Resolves: #678

[gigobyte]

All good, thanks a lot!