Can't use the new package `@dfinity/identity-secp256k1`

[Harsha]

Describe the bug
Trying to import Secp256k1KeyIdentity from the new separate package results in an error.

To Reproduce
Try importing import { Secp256k1KeyIdentity } from '@dfinity/identity-secp256k1'; in a ts file.
and you should see an error thrown by typescript about an invalid import.

And, there's no lib folder that package json is referring to:

Expected behavior
I should be able to import it

[Kai Peacock]

Thanks for calling this to my attention. I know exactly what went wrong, and I'll have a fix released today