as_dcm and from_dcm removed in scipy >= 1.6

[kaufManu]

The functions as_dcm and from_dcm in Scipy have been renamed to as_matrix and from_matrix as of Scipy 1.4. The old functions have been removed as of Scipy 1.6.

https://github.com/scipy/scipy/blob/5f4c4d802e5a56708d86909af6e5685cd95e6e66/doc/release/1.4.0-notes.rst#scipy-deprecations

Could you update these function calls or would you accept a PR?

Thanks!