[e.cash] Upgrade announcement for May 2024

Summary: Depends on D15876

Test Plan:
Read through the description to make sure the info is correct.
Ran it locally to see that it looks good.

Reviewers: Fabien, #bitcoin_abc, bytesofman

Reviewed By: Fabien, #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D15877