Migrate to Selenium 4, add Scala 3

[kubukoz]

• Drops Scala 2.11 (more recent Scala.js versions don't support it)
• Updates sbt and its plugins, as well as Scala patch versions, to allow building on modern hardware (apple silicon wasn't supported well in older releases)
• DriverFactory from Selenium isn't a thing so we make our own
• Requires Java 11 because Selenium does as well
• A DriverFactory has to be provided explicitly by the user.

[gzm0]

Hi! Thanks for taking the time to open this PR.

The overall approach looks good to me. I have left some specific comments about the interface.

A general note: We try to keep changes as isolated as possible, so ideally, we do the Scala and sbt upgrades in different PRs.

Regarding the Scala upgrade: IIUC for a library it is better to stay on the lowest possible version to not force upgrades downstream, so maybe we shouldn't do them? (dropping Scala 2.11 is of course OK). Regarding Scala 3: I have to defer to @sjrd

Lastly, there seem to be some unrelated formatting stylistic changes. We also try to avoid these as much as possible to remove noise in the diffs. If you like, I can point them out individually.

[kubukoz]

A general note: We try to keep changes as isolated as possible, so ideally, we do the Scala and sbt upgrades in different PRs.

Fair enough, I'll split.

Regarding the Scala upgrade: IIUC for a library it is better to stay on the lowest possible version to not force upgrades downstream, so maybe we shouldn't do them? (dropping Scala 2.11 is of course OK). Regarding Scala 3: I have to defer to @sjrd

As far as I understand, as long as it's under the same minor series (3.3, 2.13, 2.12) it should be fine to use a more recent version, even if users don't

Lastly, there seem to be some unrelated formatting stylistic changes. We also try to avoid these as much as possible to remove noise in the diffs. If you like, I can point them out individually.

That's alright, I'll go through the diff to make these unnecessary changes minimal. I did run scalastyle locally, it just didn't do anything :)

Thanks for your comments, I'll update the PR soon!

[kubukoz]

I couldn't keep the sbt upgrade separate as it's a prerequisite for me to literally launch sbt in the project in the first place. I could move it to a separate PR and make that the base of this one, but I'm not sure that's adding a lot of value in a project with such low traffic.

Instead, I've made it a separate commit (first one, so that the others could be rolled back independently if needed), does that work for you?

Also, new change: I didn't notice it before, but Selenium now requires JDK 11 (compiles to the classfile version 55.0), so I updated the PR description and the CI setup.

[kubukoz]

Also updated the README.

[gzm0]

Sorry for the long silence on this one. It slipped through the cracks.

There is only one nit, otherwise this LGTM to merge.

I've noticed that the CI didn't run, but I don't seem to have a button to approve it.

@sjrd do you have one? From the actions tab, it looks like you approved this last time.

[sjrd]

Huh, no, I don't have a button to run the CI. Perhaps it was too long ago? A force-push might make it appear.

[kubukoz]

try now please :)

[sjrd]

The CI did run, but it has failures.