Fix warnings in 1.20 and require Elixir 1.15+

[sabiwara]

See individual commits.

[sabiwara]

Reusing the same version as Earthfile here

[sabiwara]

Ouch it seems this breaks the earthly setup for integration files in the CI, I'm a bit out of my depth here.

[greg-rychlewski]

When we upgrade the alpine version sometimes the way we were installing things or starting the database becomes incompatible. It’s a bit annoying to debug. I can try to help out but can’t really promise how fast I can fix it

[josevalim]

Maybe we should discuss again if we should get rid of Earthfile.

[josevalim]

We can probably ask Claude Code to setup a new CI based on our constraints and it may do a reasonable good job at that. And since CI is self verifying, there is a reasonable end goal?

[greg-rychlewski]

It would probably be less headaches in the future if we redo the CI. I looked into the Postgres issue and it seems you can't install Postgres 9.5 on Alpine 3.18. Separating the database into its own container would make things easier when we upgrade the Elixir images.

After looking at it closer this isn't entirely correct. See my next message instead.

[greg-rychlewski]

The MySQL issues seem to be with the output of the dump files. They are not matching exactly what we expected. So I don't expect that to be a major issue to fix. I can look at that.

For Postgres I just checked and actually all version are EOL until Postgres 13. We could just stop running 9.5 on the CI and replace it with 13 or 12 or something like that. If we want to immediately unblock this.

And actually I made a mistake with my previous message. The database is running in a separate container but it was the client utilities that were failing. There is a comment in the Earthfile that Postgres 9.5 needs to pin its version and can't use newer clients. I don't think we can fix that so probably the only solution is to stop using 9.5 in the CI

[greg-rychlewski]

Sent a PR with minimal CI changes to get this working for now: #719

That's not to exclude the possibility of redoing the CI but these changes seem reasonable enough to me to get the warnings fixed for elixir 1.20