MySQL upstream: could not use requested auth plugin 'mysql_native_password'

[tobiasholst]

thank you very much for this great package. Unfortunately the mysql upstream does not work with a fresh mariadb/mysql docker container.

docker log:

`Version : v0.4.2dev
Go Runtime : go1.12.6
Git Commit : 349c62a,2019-05-24

[sshpiperd]
listen = 0.0.0.0
port = 2222
server-key = /etc/ssh/ssh_host_rsa_key
upstream-driver = mysql
challenger-driver =
auditor-driver =
banner-text =
banner-file =
log =
log-flags = 3

[upstream.mysql]
upstream-mysql-host = pipe-db
upstream-mysql-user = piper
upstream-mysql-password = piper
upstream-mysql-port = 3306
upstream-mysql-dbname = piper

2019/06/26 14:04:58 sshpiper is about to start
[mysql] 2019/06/26 14:04:58 driver.go:123: could not use requested auth plugin 'mysql_native_password': this user requires mysql native password authentication.
this user requires mysql native password authentication.
`