Grafana: Upgrades mysql images from 5.7 to 8

[owensmallwood]

Adding a build step for mysql8 since we're transitioning to that in cloud.

Enterprise PR

[papagian]

There some additional references of the 5.7.39 version that we need to address here or in a follow-up:

• the default version in mysql devenv block
• the default version in mysql_tests devenv block
• the default argument for the mysql_tests Dockerfile

[sakjur]

🤔 I'm a bit worried that we could end up depending on MySQL 8 features in a migration somewhere without detecting it before shipping since we've committed to supporting MySQL 5.7 (https://grafana.com/docs/grafana/v9.5/setup-grafana/installation/#supported-databases) until it's no longer supported by upstream.

[sakjur]

This file needs to be generated with make drone.

[papagian]

🤔 I'm a bit worried that we could end up depending on MySQL 8 features in a migration somewhere without detecting it before shipping since we've committed to supporting MySQL 5.7 (https://grafana.com/docs/grafana/v9.5/setup-grafana/installation/#supported-databases) until it's no longer supported by upstream.

that's also my concern: ideally we would like to run integration tests both against 5.7 and 8.0

[kminehart]

ideally we would like to run integration tests both against 5.7 and 8.0

Good idea!

[owensmallwood]

@sakjur @kminehart @papagian How much work would it be to have our mysql integration tests run against 5.7 and 8? I'm not really familiar with our build pipepine. This PR was mostly to see what would break if we bump the mysql image to 8.

[sakjur]

I don't think that would be a lot of work, I'll create a branch to try it out quickly

[sakjur]

Got it working in #67710.

[owensmallwood]

Thanks @sakjur . I'll do the same thing to the enterprise PR for this

[owensmallwood]

@sakjur Do you know how long we're committed to supporting 5.7? Assuming until EOL in October?

[sakjur]

Yup, October.