new example: buoyant-bubble with a Boussinesq system (velocity extrapolation in time + pressure solver); devops tests bump

[slayoo]

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[slayoo]

@Caastlefox, not to forget:

• label for the colorscale (temperature [K])
• brief description of what equations are solved, and where the settings originate from
• @jit decorator for more functions
• at least a minimal smoke test

To fix the precommit formatting issue, you need to pip install pre-commit, and then either do pre-commit install (which will trigger pre-commit formatting changes before each commit) or trigger the scan manually with pre-commit run --all-files. HTH