deps: bump Rollup peerDep to 3.7.5+, remove tech debt

[agilgur5]

Summary

Bumping the Rollup peerDep and removing legacy tech debt workarounds

• As discussed in https://github.com/ezolenko/rollup-plugin-typescript2/issues/435#issuecomment-1629852786

Details

Rollup upgrade

• 3.7.5 includes https://github.com/rollup/rollup/pull/4749
  • which fixes the duplicate error logging upstream and allows us to remove the buildEnd workaround from #373
• 2.60.0 includes this.load, so can remove the satisfies check
• 2.14.0 includes this.meta.watchMode, so can remove the env check

Other tech debt removals

Figured I'd remove some other deprecated code / tech debt while I'm at it

• remove deprecated rollupCommonJSResolveHack
  • it hasn't done anything since #251 in late 2020 (~2.5 years ago)
  • and has been formally deprecated since #367 over a year ago
• remove objectHashIgnoreUnknownHack warning
  • hasn't been needed for async functions since #203 in early 2020 (~3.5 years ago) - so I think that's a long enough window to now remove the warning
  • also add a link in the docs to object-hash
  • noticed there wasn't one, despite all the links I added to the docs!

[agilgur5]

Left this as a Draft PR for now as it is breaking, and I think we should get in a patch release and stabilize MTS/CTS support beforehand.

453 would be ideal to get in beforehand as well, although that is technically a breaking change as well

And potentially there is more tech debt we want to remove in this PR as well; thought I might be missing something?

[agilgur5]

ooo tests caught that devDeps need updating too! awesome to see integration tests reaping rewards 🙂 updating Rollup to 3+ requires updating several plugins as well, so I'm gonna need to review some breaking changes for those

[agilgur5]

Proactively bumped the repro template to use Rollup v3 (and TS v5 and rpt2 v0.35)

[ezolenko]

Last time I tried to just update everything updatable, I got a lot of grief from tsjest

[agilgur5]

Yea I noticed from #447 😅 ESM adoption has (expectedly) caused a bit of churn in the ecosystem.

Though this PR specifically only needs to update all the Rollup deps, so maybe won't need updating the rest. But seems I might need to do so for #460 anyway