Upgrade to Python 3.12

[jonaharagon]

Changes proposed in this PR:

• Use Python 3.12 for builds.

Ignore the failing PR builds, it's a side-effect of how the actions work, but the 3.12 builds are confirmed working here: https://github.com/privacyguides/privacyguides.org/actions/runs/8497606307

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