Bug#1121626: libdune-common-dev: dune config scripts use python pkg_resources

[Drew Parsons]

Package: libdune-common-dev
Version: 2.10.0-5
Severity: normal

libdune-common-dev provides /usr/share/dune/cmake/scripts/pyversion.py,
which uses pkg_resources.

Previously pkg_resources was a standard python module but is now
deprecated and no longer installed by default by the core python3
package.  Packages that need it should probably update to use setuptools
(see https://setuptools.pypa.io/en/latest/pkg_resources.html),
and the python3-setuptools package does Depends: python3-pkg-resources.

The problem with libdune-common-dev can be seen in the test log for opm-grid,
https://ci.debian.net/packages/o/opm-grid/unstable/amd64/66648203/

 68s -- Found Python3: /usr/bin/python3 (found version "3.13.9") found components: Interpreter Development Development.Module Development.Embed
 68s -- Failed to find the python package pip with interpreter /usr/bin/python3. (missing: DUNE_PYTHON_pip_FOUND) 
 68s -- Failed to find the python package virtualenv with interpreter /usr/bin/python3. (missing: DUNE_PYTHON_virtualenv_FOUND) 
 68s Traceback (most recent call last):
 68s   File "/usr/share/dune/cmake/scripts/pyversion.py", line 32, in <module>
 68s     import pkg_resources
 68s ModuleNotFoundError: No module named 'pkg_resources'
 
Evidently it's not fatal for opm-grid, which goes on to build and run its tests
(I guess opm/dune should be updated to use cmake commands like
find_package(Python) instead of custom scripts like pyversion.py)

Nevertheless it looks like libdune-common-dev ought to have a
   Recommends: python3-pkg-resources
alongside the current Recommends: python3