Update dependency phpunit/phpunit to v8.4.3

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
phpunit/phpunit (source)	require-dev	patch	8.4.2 -> 8.4.3

---

Release Notes

sebastianbergmann/phpunit

### [`v8.4.3`](https://togithub.com/sebastianbergmann/phpunit/compare/8.4.2...8.4.3) [Compare Source](https://togithub.com/sebastianbergmann/phpunit/compare/8.4.2...8.4.3)

---

Renovate configuration

:date: Schedule: At any time (no schedule defined).

:vertical_traffic_light: Automerge: Disabled by config. Please merge this manually once you are satisfied.

:recycle: Rebasing: Whenever PR becomes conflicted, or if you modify the PR title to begin with "rebase!".

:no_bell: Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box

---

Newsflash: Renovate has joined WhiteSource, and is now free for all use. Learn more or view updated terms and privacy policies.