chore(deps): update dependency postcss to v8.5.15

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
postcss (source)	8.5.10 → 8.5.15

---

Release Notes

postcss/postcss (postcss)

v8.5.15

Compare Source

• Fixed declaration parsing performance (by @​homanp).

v8.5.14

Compare Source

• Fixed custom syntax regression (by @​43081j).

v8.5.13

Compare Source

• Fixed postcss-scss commend regression.

v8.5.12

Compare Source

• Fixed reading any file via user-generated CSS.
• Added opts.unsafeMap to disable checks.

v8.5.11

Compare Source

• Fixed nested brackets parsing performance (by @​offset).

---

Configuration

📅 Schedule: (UTC)

• Branch creation
  • At any time (no schedule defined)
• Automerge
  • At any time (no schedule defined)

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR is behind base branch, 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 was generated by Mend Renovate. View the repository job log.