Update the miner fund address
Summary:
As per title. Because this is consensus, it needs to happen during an upgrade.
Test Plan:
ninja check-extended
Run IBD.
Reviewers: #bitcoin_abc, Mengerian
Reviewed By: #bitcoin_abc, Mengerian
Subscribers: Mengerian, PiRK
Differential Revision: https://reviews.bitcoinabc.org/D11075