MAINT: Finalize rename to main

[HaoZeke]

Part of #1368.

[mattip]

Could you add a release note? I think this could have an impact on projects that still use `master' as the default branch: they will need to now use a non-default configuration, right?

[HaoZeke]

Could you add a release note? I think this could have an impact on projects that still use `master' as the default branch: they will need to now use a non-default configuration, right?

I'm not sure it will though, if the projects have an existing asv.config.json they shouldn't be affected. Internally asv still assumes master even after this simply because asv shouldn't be responsible for making changes to git configurations and that still defaults to master. The default example config has changed, but that shouldn't be a breaking change.

I will add a release note.

[mattip]

Thanks @HaoZeke

[mattip]

The release note can be part of the general release