docs: Suggest a blobless clone instead of a shallow clone (#64693)
GitHub recommends blobless clones over shallow clones:
https://github.blog/2020-12-21-get-up-to-speed-with-partial-clone-and-shallow-clone/
> For these reasons we do not recommend shallow clones except for builds
that delete the repository immediately afterwards. Fetching from shallow
clones can cause more harm than good!
I've been using blobless clones for development for the last couple
weeks. The blobless clone has the benefit of including the full
repository history (for the cloned branch). Tools like `git blame` will
be slower as git fetches the related blobs on-demand.
Benchmarks (using all the flags in the docs):
- The blobless clone is faster on my machine, taking 11.1 seconds versus
13.1 seconds for the shallow clone.
- The blobless clone takes up 256M on disk, versus 244M for the shallow
clone. It's worse, but not by much.