Depend on tar-0.6.3.0 (backport #10120)

[mergify]

tar-0.6.3.0 has much improved performance of deserialising .tar index
which has significant ramifications for the start-up time of
cabal-install.

See #10110

---

This is an automatic backport of pull request #10120 done by Mergify.

[mergify]

Cherry-pick of 4d787e1 has failed:

On branch mergify/bp/3.12/pr-10120
Your branch is ahead of 'origin/3.12' by 1 commit.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit 4d787e1b5.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   bootstrap/generate_bootstrap_plans
	modified:   cabal.bootstrap.project

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   bootstrap/linux-8.10.7.json
	both modified:   bootstrap/linux-9.0.2.json
	both modified:   bootstrap/linux-9.2.8.json
	both modified:   bootstrap/linux-9.4.8.json
	both modified:   bootstrap/linux-9.6.4.json
	both modified:   bootstrap/linux-9.8.2.json

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally