Fix physics example

[3demax]

I was playing around with the library (thanks for publishing, BTW) and noticed that physac.py example wasn't working well, because "UpdatePhysics" function was not defined:

Traceback (most recent call last):
  File "/home/max/Projects/Projects/Dichronauts/raylib/physac.py", line 27, in <module>
    UpdatePhysics()  # TODO no longer works
    ^^^^^^^^^^^^^
NameError: name 'UpdatePhysics' is not defined

So I just commented it out and to my surprise it worked well :D

I digged a bit deeper to try to figure out what happened and realized that it seems like physac was updated (to v1.1) since initial bindings were created.
It still has InitPhysics, but now it seems to include it's own, so you don't need to call UpdatePhysics anymore.
ResetPhysics was removed, but nobody stops you to ClosePhysics(); InitPhysics() to the same effect.

That's what I did and now it works as expected:

[electronstudio]

The version of Physac that we ship with has UpdatePhysics:

https://github.com/raysan5/physac/blob/4a8e17f263fb8e1150b3fbafc96f880c7d7a4833/src/physac.h#L201

I think you are trying to use a newer version of Physac.

[electronstudio]

There’s a proposal to use the newer version here

#165

but until/unless this is done the examples should not be updated.

[3demax]

I have decided to reach out because I ran into errors with physics example in the the package for nixOS.

It builds fine, but it uses an upstream version of physac (which is currently 1.1), instead of the local one.
Technically, I can force it to build against the old version of Physac, but I don't know if that makes sense, since building against the most recent upstream version works well, even though with some caveats.

[electronstudio]

Sounds like an issue with the Nixos package then. I mean you can build raylib-python-CFFI against any versions you want. You could make a package with Raylib 5.6-dev right now. But it would be wrong to confuse these packages with mine.

[3demax]

Fair point. I just realized how this might look from your perspective: you have pulled in very specific versions of c libraries to make sure it all works and here I am tearing it apart and building against the versions that I like.

This is something I wanted to follow-up, but let me bring this up in another conversation.

[electronstudio]

No problem with you using whatever versions you like, and I will eventually merge this PR when I update Physac.

Issue seems to be Nixos has broken it up into separate packages for Raylib-Python-CFFi, Raylib, Raygui and GLFW. Which is fine, it still builds a valid Raylib-Python-CFFI. But it doesn’t build Raylib-Python-CFFI 5.5.0.2 unless all those package versions match ours, and they don’t. So either NixOS needs to specify specific versions of those dependencies, or else not claim the resultant package is 5.5.0.2.