Support for python 3.11

[jsoishi]

It appears that skfmm/pheap.cpp needs to be re-Cythonized for python 3.11 support. When I attempt to pip install, there is no binary, and the build fails with the following error:

     INFO: compile options: '-I/tmp/pip-build-env-hs0al687/overlay/lib/python3.11/site-packages/numpy/core/include -Ibuild/src.linux-x86_64-3.11/numpy/distutils/include -I/home/jsoishi/miniforge3/envs/scikit-test/include/python3.11 -c'
      extra options: '-msse -msse2 -msse3'
      INFO: g++: skfmm/pheap.cpp
      INFO: g++: skfmm/heap.cpp
      skfmm/pheap.cpp: In function ‘void __Pyx_AddTraceback(const char*, int, int, const char*)’:
      skfmm/pheap.cpp:446:62: error: invalid use of incomplete type ‘PyFrameObject’ {aka ‘struct _frame’}
        446 |   #define __Pyx_PyFrame_SetLineNumber(frame, lineno)  (frame)->f_lineno = (lineno)
            |                                                              ^~
      skfmm/pheap.cpp:3360:5: note: in expansion of macro ‘__Pyx_PyFrame_SetLineNumber’
       3360 |     __Pyx_PyFrame_SetLineNumber(py_frame, py_line);
            |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~
      In file included from /home/jsoishi/miniforge3/envs/scikit-test/include/python3.11/Python.h:42,
                       from skfmm/pheap.cpp:6:
      /home/jsoishi/miniforge3/envs/scikit-test/include/python3.11/pytypedefs.h:22:16: note: forward declaration of ‘PyFrameObject’ {aka ‘struct _frame’}
         22 | typedef struct _frame PyFrameObject;
            |                ^~~~~~
      error: Command "g++ -pthread -B /home/jsoishi/miniforge3/envs/scikit-test/compiler_compat -DNDEBUG -fwrapv -O2 -Wall -fPIC -O2 -isystem /home/jsoishi/miniforge3/envs/scikit-test/include -fPIC -O2 -isystem /home/jsoishi/miniforge3/envs/scikit-test/include -fPIC -I/tmp/pip-build-env-hs0al687/overlay/lib/python3.11/site-packages/numpy/core/include -Ibuild/src.linux-x86_64-3.11/numpy/distutils/include -I/home/jsoishi/miniforge3/envs/scikit-test/include/python3.11 -c skfmm/pheap.cpp -o build/temp.linux-x86_64-cpython-311/skfmm/pheap.o -MMD -MF build/temp.linux-x86_64-cpython-311/skfmm/pheap.o.d -msse -msse2 -msse3" failed with exit status 1

[jkfurtney]

Thanks for the note on this, I will get to this as soon as I can. If we Cythonize this for 3.11, will it break the earlier versions? Maybe we should add the cythonization as part of the build? If you have time to do it and create a PR I will merge it and we can see if the build servers pass. We should also add a 3.11 build on the build servers.

[jkfurtney]

The 3.11 build works now. I will make a release.