databases/mysq56-{client, server}: Update to 5.6.45

This update includes security fixes which are
mentioned on upstream critical patch report.
Further info:
https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html#AppendixMSQL

PR: 239571
Reported by: serg@tmn.ru
Sponsored by: Platform.sh