Tweaks to Gradient° doc for v3 release (#160)
Tweaks to Gradient° doc for v3 release (#160)

* Update name of Fast.AI container

* fix: update gradient create notebook image and add note about preemptible instance types

fastai/course-v3,fastai/course-v3,fastai/course-v3,fastai/course-v3,fastai/course-v3,fastai/course-v3,fastai/course-v3