Release 2.7.1

Skip musllinux wheels: crbfgs cannot resolve BLAS there

On musllinux the crbfgs link against the staged libscipy_openblas.so succeeds,
yet the module comes out with no BLAS in DT_NEEDED and no BLAS routines of its
own, so it would fail at import with 'undefined symbol: dnrm2_'.  auditwheel
cannot help either, as there is no dependency for it to vendor.  manylinux does
record the dependency and is unaffected.

This is not a new break: it predates the build_ext check that now catches it,
so the musllinux wheels published before this were almost certainly already
broken at import.  Skip the platform rather than publish more of them.

Whether this is fixable with -Wl,--no-as-needed depends on whether that .so
exports the F77 symbols at all; the note in pyproject.toml records the command
to check before revisiting.

Co-Authored-By: Claude <noreply@anthropic.com>