Set main branch to linear history

[xmfcx]

In Autoware repositories we protect the main branch with the Require linear history rule to keep main branch less complicated.

• https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/managing-protected-branches/about-protected-branches#require-linear-history

Steps to enable it:

• https://github.com/tier4/AWSIM/settings/branches
• main -> Edit -> Check Require linear history -> Save changes

Some reasoning:
https://stackoverflow.com/a/76321945/4520129

• No code changes are hidden inside merge commits as conflict resolution. Each diff belongs to single commit with its message explaining the reason behind the change.
• Conflicts are conceptually easier to resolve during rebase than during merge, as the resolution takes place in a "context" of single commit (as opposed to entire branch). This reduces potential conflict resolution mistakes.

I understand if you don't want it too, it is a bit subjective.

[mackierx111]

Thanks for the suggestion! good idea. I have applied the changes.

[xmfcx]

Thank you so much!