add windows ci

[esheldon]

No description provided.

[esheldon]

Not a good sign. Doesn't know about the build system and it is trying to use unix style paths with / instead of \

checking build system type... x86_64-pc-mingw64
  checking host system type... x86_64-pc-mingw64
  checking target system type... x86_64-pc-mingw64
  cfitsio: == Don't know what to do with x86_64-pc-mingw64
  checking for cc... no
  checking for gcc... gcc
  checking whether the C compiler works... no
  configure: error: in `/tmp/tmp92t8tgmq.build-temp/Release/cfitsio-4.4.1-20240617':
  configure: error: C compiler cannot create executables

[esheldon]

https://heasarc.gsfc.nasa.gov/FTP/software/fitsio/c/README.win

[esheldon]

I don't understand why its trying to install numpy here, its already installed

  Installing backend dependencies: started
  Installing backend dependencies: still running...
  Installing backend dependencies: finished with status 'error'
  error: subprocess-exited-with-error
  
  pip subprocess to install backend dependencies did not run successfully.
  exit code: 1
  
  [408 lines of output]
  Collecting numpy
    Downloading numpy-2.0.0.tar.gz (18.3 MB)
       --------------------------------------- 18.3/18.3 MB 50.4 MB/s eta 0:00:00
    Installing build dependencies: started
    Installing build dependencies: still running...
    Installing build dependencies: finished with status 'error'
    error: subprocess-exited-with-error
  
    pip subprocess to install build dependencies did not run successfully.
    exit code: 1

[esheldon]

Here's a clue. It is ignoring the existing numpy install because it wants to build everything from scratch

WARNING: Implying --no-binary=:all: due to the presence of --build-option / --global-option.