Update python:3.8.1-alpine Docker digest to f21927a

This MR contains the following updates:

Package	Type	Update	Change
python	final	digest	8412de9 -> f21927a

---

Renovate configuration

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

🚦 Automerge: Enabled.

♻ Rebasing: Whenever MR is stale.

🔕 Ignore: Close this MR and you won't be reminded about this update again.

---

• If you want to rebase/retry this MR, check this box