Change branch name from master to main

[carols10cents]

Connects to #1687.

This will need someone with the right permissions to actually do the branch rename :)

[senekor]

Maybe @rust-lang/infra has the permissions? (or knows who does...)

[Kobzol]

Yes, this pretty much has to be done by an infra admin. A PR also has to be sent to the team repo to update branch protections.

[marcoieni]

This PR looks good to me.
I'm an infra admin, I can do this change. Here's the plan I propose:

• change the default branch in the settings
• merge this PR
• merge blog repo: change branch protection pattern from 'master' to 'main' team#1976

Does the sequence looks right?

[senekor]

Maybe it's possible to protect both master and main in the pattern? Then the team repo PR can be merged first, so there is no "downtime" for the branch protection.

[Kobzol]

I don't think that's needed, but it would also work.

[marcoieni]

I also don't think it's needed to protect both main and master since I will perform the steps quickly 👍
I will execute the plan once rust-lang/team#1976 is approved. I'm pinging someone

[Kobzol]

Note that promote-release might require an update for this (https://github.com/rust-lang/promote-release/blob/ee6866331f1d61fc9faa5df00bc0305eb7a2ad65/src/main.rs#L37).

[marcoieni]

oh, ok, than: we should wait for rust-lang/promote-release#95 to be deployed first 👍

[Kobzol]

(My PR doesn't fix this, it only removes master references for r-l/r, not the blog.)

[marcoieni]

oh, I see, so we need to open another PR to fix it 👍