Add support for show slave status

[fulghum]

This syntax is deprecated and will be removed in future MySQL versions (SHOW REPLICA STATUS should be preferred instead). However, some tools (e.g. Dolphie, MyDumper) still rely on this deprecated syntax, so we're adding support for it to keep compatibility with those tools.

[jycor]

LGTM

[davidducos]

Hi @fulghum, MyDumper supports both (SLAVE and REPLICA) and depending on the version determine which is the best to use, which in MySQL is since version 8.0.22.
I check the version that Dolt is reporting and it says 8.0.11, that is why mydumper uses SLAVE, instead of REPLICA, if you start using a version number above 22, it will automatically change to REPLICA. BTW, I already working on this PR mydumper/mydumper#1684 in case that you know specific cases that you want to implement for Dolt. Please, let me know if you consider this useful, if not, it will consider as a Unknown version and it will apply the same rules than MySQL and Percona.
Cheers

[fulghum]

Hi @davidducos, thanks for chiming in! Awesome to see that you've already got a PR in progress with some changes to better support Dolt! 🙌 Thank you! @jycor is working on some Dolt changes on on our side, too, so we'll get him to try out sending a different MySQL version number and to take a look at the PR you linked to. Thanks for the help!

[davidducos]

Ok, the PR on mydumper side is on hold now, until we get the version number on Dolt, as we could use just 8.0.11 but I want your users get a better experience setting the right number. Please let me know so I can merge that.
Cheers!