Docs: Update the 'Major Release Steps' docs for what we did to release v6

[JoshuaKGoldberg]

Before You File a Documentation Request Please Confirm You Have Done The Following...

• I have looked for existing open or closed documentation requests that match my proposal.
• I have read the FAQ and my problem is not listed.

Suggested Changes

We've done a few things to prep v6 that aren't in the docs yet. They should be documented.

At the very least:

• Configs: Apply changes to config presets for v6 #6759
• Try out v6 beta on various important community repos #6760
• Writing & sharing out a blog post
• Creating a Discord channel

Affected URL(s)

https://typescript-eslint.io/maintenance/releases#major-release-steps

[JoshuaKGoldberg]

Additionally:

• Retarget any PRs against main, as GitHub closed our PR against v6 and isn't giving us the option to reopen them 😡 (example: fix(eslint-plugin): fix schemas across several rules and add schema tests #6947)
  • Edit: aha! if you create a new branch with the same name as the old one, you can reopen the PRs! 💡
• The blog post is actually twofold: first one for the beta, then one for the release (Docs: Release blog post for v6 #7153)
• The merge should be done with a traditional merge commit, not a squash one - so that setting has to be temporarily enabled for the repo

[JoshuaKGoldberg]

I think we'll need to update the list of expected status checks for the PRs whenever we update a Node version, too.

[bradzacher]

I think we'll need to update the list of expected status checks for the PRs whenever we update a Node version, too.

I just did that yeah - that's not specifically a major release thing though - that's just a CI change step - but we happened to change the min AND max node versions in this major which meant that all the old required steps are now out-of-date.

I just updated it all.
Steps are:

1. https://github.com/typescript-eslint/typescript-eslint/settings/branches
2. edit the main branch protection
3. remove the now obsolete steps from "Status checks that are required."
4. add the new steps to "Status checks that are required."

NOTE: this sucks, the UI sucks, and it's a pain in the ass to do, sadly.

[JamesHenry]

TODO for this is updating the text to reference nx release rather than lerna and tweak the instructions accordingly