Enable "Always suggest updating pull request branches" (align with py-libp2p)

Summary

multiformats/py-multiaddr and libp2p/py-libp2p use different GitHub repository settings for keeping PR branches in sync with the default branch.

(allow_update_branch is the API field for the UI option Settings → General → Pull Requests → Always suggest updating pull request branches.)

Why it matters

When this setting is disabled, GitHub often does not show the Update branch control on a PR—even if the branch is behind master and merges cleanly—unless branch protection requires branches to be up to date before merging.

Maintainers and contributors may still merge (squash/rebase/merge commit), but syncing the PR branch with the latest default branch is less discoverable: authors are more likely to rely on manual git fetch / git merge origin/master (or rebase) on their fork.

With the setting enabled (as on py-libp2p), GitHub suggests Update branch / Update with rebase when a PR is behind the base branch, has no conflicts, and the viewer has permission to update the head branch (docs).

This came up while reviewing fork PRs where local git rev-list showed divergence from origin/master, but the GitHub UI did not offer Update branch on py-multiaddr.

Proposal

Enable Always suggest updating pull request branches on multiformats/py-multiaddr to match libp2p/py-libp2p, unless there is a deliberate reason to keep it off.

Tasks (maintainers)

• Repo Settings → General → Pull Requests → enable Always suggest updating pull request branches
• (Optional) Note the convention in contributor docs if we document PR workflow anywhere

Notes

• This does not force PRs to be up to date before merge; it only makes the update action easier to find when appropriate.
• Update branch still requires write access to the repository that owns the PR head branch (fork authors, or upstream maintainers when Allow edits by maintainers is enabled on the PR).

Open the repository's Settings → General → Pull Requests page and compare the setting with libp2p/py-libp2p. Done means enabling “Always suggest updating pull request branches” for multiformats/py-multiaddr; optionally check whether contributor documentation should note the convention.