fix(@angular-devkit/build-angular): upgrade postcss to 8.5.12

[alan-agius4]

This addresses GHSA-qx2v-qp2m-jg93

Fixes: #33067

[gemini-code-assist]

Code Review

This pull request updates the postcss dependency from version 8.5.2 to 8.5.12 in the root and package-level package.json files, with corresponding updates in pnpm-lock.yaml. Feedback suggests that the old, potentially vulnerable versions of postcss and nanoid still persist in the lockfile and should be pruned if they are no longer required to avoid triggering security scanners.

[alan-agius4]

This PR was merged into the repository. The changes were merged into the following branches:

• 19.2.x: 49ae0ad

[angular-automatic-lock-bot]

This pull request has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}