readme.md's versions may cause errors on MacOS

[Pennswood]

If you are using the following dependencies (as suggested by the readme.md file):

blas-src = { version = "0.2.0", default-features = false, features = ["openblas"] } openblas-src = { version = "0.6.0", default-features = false, features = ["cblas", "system"] }

and are getting the following errors:
error: linking with cc failed: exit status: 1 [huge note of directories] = note: ld: library not found for -lgfortran clang: error: linker command failed with exit code 1 (use -v to see invocation)

Use instead:

'ndarray = { version = "0.15.0", features = ["blas"] }
blas-src = { version = "0.8", features = ["openblas"] }
openblas-src = { version = "0.10", features = ["cblas", "system"] }
'

seems have have solved the issue for me on MacOS.