Update dependency pytest-homeassistant-custom-component to v0.13.21

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
pytest-homeassistant-custom-component	==0.13.19 -> ==0.13.21

---

Release Notes

MatthewFlamm/pytest-homeassistant-custom-component

### [`v0.13.21`](https://togithub.com/MatthewFlamm/pytest-homeassistant-custom-component/releases/tag/0.13.21) [Compare Source](https://togithub.com/MatthewFlamm/pytest-homeassistant-custom-component/compare/0.13.20...0.13.21) Automatic release homeassistant version: 2023.4.4 ### [`v0.13.20`](https://togithub.com/MatthewFlamm/pytest-homeassistant-custom-component/releases/tag/0.13.20) [Compare Source](https://togithub.com/MatthewFlamm/pytest-homeassistant-custom-component/compare/0.13.19...0.13.20) Automatic release homeassistant version: 2023.4.3

---

Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

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

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 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

---

This PR has been generated by Mend Renovate. View repository job log here.