[chronik] Set the version number to follow the version of bitcoind

Summary: Having a separate version number for chronik makes no sense since it's built-in bitcoind.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, bytesofman, tobias_ruck

Reviewed By: #bitcoin_abc, bytesofman, tobias_ruck

Subscribers: tobias_ruck, bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D16809