mysql:8 caching_sha2_password

[earlgreyz]

Since MySQL 8, the mysql_native_password is replaced with caching_sha2_password which causes following error with the mysqlclient version 5.7 (used by grtl/xtrabackup:latest)

ERROR 2059 (HY000): Authentication plugin 'caching_sha2_password' cannot be loaded:
/usr/lib64/mysql/plugin/caching_sha2_password.so: cannot open shared object file: No such file or directory

As a temporary solution I recommend using the option to specify custom mysql image with version < 8.0.