[eCash dev libraries] [p14 ecash ops] Patch typo in readme and publish new version to correct

Summary:
T2847

Depends on D12870

Per feedback in part 12 of this stack, correct readme error. Because the only way to fix this in the public facing repo description is to publish a new version, publish a new version.

Test Plan: Confirm README link is now correct.

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D12881