BLD: only check for scipy-openblas dependency with pkg-config

This is a custom-built wheel that can only be detected through
pkg-config. So trying other methods just costs time and increases
the size of `meson-log.txt`.

numpy/meson.build

@@ -93,7 +93,7 @@ mkl_may_use_sdl = not use_ilp64 and _threading_opt in ['auto', 'iomp']
 # First try scipy-openblas, and if found don't look for cblas or lapack, we
 # know what's inside the scipy-openblas wheels already.
 if blas_name == 'openblas' or blas_name == 'auto'
-  blas = dependency('scipy-openblas', required: false)
+  blas = dependency('scipy-openblas', method: 'pkg-config', required: false)
   if blas.found()
     blas_name = 'scipy-openblas'
   endif