configure: UniValue 1.0.4 is required for pushKV(, bool)

Summary: THis is a backport of core PR12666

Test Plan:

make check

Reviewers: #bitcoin_abc, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1900