Release notes 0.18.1

Bitcoin ABC version 0.18.1 is now available from:

https://download.bitcoinabc.org/0.18.1/

This release includes the following features and fixes: - Fix a mining bug that affects block creation, impact after Nov upgrade. - Fix a bug that could result in dropping transactions from re-orgs, impact after Nov upgrade. - Reserve a range for multi byte opcodes in the script system. - Various test fixes, speedups, and refactors.