Deprecate checkpointing (cornellius-gp#2361)

* Deprecate checkpointing

* Remove checkpointing from test

Update linear operator dependency (cornellius-gp#2321)

pass **kwargs to ApproximateGP.__call__ in DeepGPLayer (cornellius-gp…

…#2224)

Co-authored-by: root <root@com120226.localdomain>
Co-authored-by: Geoff Pleiss <gpleiss@gmail.com>

Enable automatic versioning via setuptools_scm (cornellius-gp#2111)

* Enable automatic versioning via setuptools_scm

Based on cornellius-gp/linear_operator#2

* Resolve RTD warnings from example notebooks

Update test suite badge