Dependency `conformer` is unmaintained, source repository has disappeared

[hoh]

The source repository of the conformer library has disappeared, as well as the GitHub account of the author.

https://github.com/lucidrains/conformer returns a 404

The only artifacts remaining are on PyPI: https://pypi.org/project/conformer/#history (almost 3 years old).

Related to #130 and #134.