MAINT,DOC: pip and network connectivity defaults

[HaoZeke]

Closes #1356.

[mattip]

Is there a sample test project with a pyproject.toml?

[HaoZeke]

Is there a sample test project with a pyproject.toml?

Yes, (linked in the documentation, also here) but it needs a newly released asv_runner first, will prepare the release ASAP.

[HaoZeke]

@mattip this should now be good to go (last one for the release!!).

[HaoZeke]

CI failure is real, needs the backport importlib_metadata on 3.7, cutting a new bugfix release for asv_runner. Fixed.

[HaoZeke]

@mattip finally ready ^_^

[mattip]

Thanks @HaoZeke