Bug#1096194: python3-cffi: bump priority to Depends: python3-dev

[Drew Parsons]

Followup-For: Bug #1096194
Control: reassign 1096194 src:scifem

No, this was a misdiagnosis.

python3-ffcx already does have Depends: python3-dev

The issue here is that scifem tests do not explicitly require
python3-dev, and then, more to the point, the scifem test is failing
with Python 3.12.

That is, python3-dev is already installed, as it should be for normal
ffcx operations. But that only loads the default Python version.

scifem wants to test all python versions,
so it needs to be explicit about it,
Depends: python3-all-dev

Stefano Rivera wrote:
> An option here would be to add a python3-cffi-inline package, that
> depends on: python3-cffi, python3-dev, build-essential

Same point as above, though. It's the non-default python 3.12 causing
the problem.  I think the scifem tests just need python3-all-dev