Add python3-pkg-resources to dependencies

[fthaltun]

On Debian 13.2, if the python3-pkg-resources package is not installed, warpinator fails to start and prints the following error:

No module named 'pkg_resources'

After installing python3-pkg-resources, the application launches successfully.

[mtwebster]

It looks like one place we import this it's no longer even used (the code that used it was removed in this commit).

I think if you try removing it from server.py (https://github.com/linuxmint/warpinator/blob/master/src/server.py#L9, or in its installed location in /usr/libexec/warpinator/server.py), we can just drop it altogether (the module is being retired anyhow).

[fthaltun]

Yes, deleting https://github.com/linuxmint/warpinator/blob/master/src/server.py#L9 is sufficient.

Note: https://github.com/linuxmint/warpinator/blob/master/src/protobuf-6.31.1/google/__init__.py#L2 throws an exception here and passes to pkgutil, no problem.