Update to CMake 3.29.0

[henryiii]

Created by running nox -s bump -- --commit

I've also pushed a final py2 release with scikit-build classic of 3.28.4 with Python 2 support fixed (it's been broken for quite a while, at least accessing it from Python has).

[henryiii]

This is failing on MUSL with the following error:

 CMake Error at /project/CMake-src/Tests/RunCMake/RunCMake.cmake:280 (message):
      Stub-fail - FAILED:
  
      stderr does not match that expected.
  
      Command was:
  
       command> "/project/build/py3-none-musllinux_1_1_x86_64/CMakeProject-build/bin/cmake" "-E" "env" "LANG=C" "/project/build/py3-none-musllinux_1_1_x86_64/CMakeProject-build/Tests/RunCMake/RuntimePath/Stub-build/StubExe"
  
      Actual stdout:
  
       actual-stdout>
  
      Expected stderr to match:
  
       expect-stderr> (error while loading shared libraries: libStub\.so\.1|Library not loaded: '?@rpath/libStub\.1\.dylib'?|(Cannot|Could not) load module libStub\.so|fatal: libStub\.so\.1: open failed|Shared object "libStub\.so\.1" not found)
  
      Actual stderr:
  
       actual-stderr> Error loading shared library libStub.so.1: No such file or directory (needed by /project/build/py3-none-musllinux_1_1_x86_64/CMakeProject-build/Tests/RunCMake/RuntimePath/Stub-build/libStubUse.so)
       actual-stderr> Error relocating /project/build/py3-none-musllinux_1_1_x86_64/CMakeProject-build/Tests/RunCMake/RuntimePath/Stub-build/libStubUse.so: Stub: symbol not found
  
    Call Stack (most recent call first):
      /project/CMake-src/Tests/RunCMake/RunCMake.cmake:288 (run_cmake)
      /project/CMake-src/Tests/RunCMake/RuntimePath/RunCMakeTest.cmake:56 (run_cmake_command)