backport_pr: Only works for when fork is in user (not in organization)

[chrysn]

Description

Users who forked the RIOT repository into an own organization can't asily use dist/tools/backport-pr/backport_pr.py. This has two reasons:

• The repository name username / REPO is part of backport_pr.py. This is easy to fix by hardcoding the right repo name -- if we could fix the rest, I'd make that an argument.

• The personal token issued as described in the README is insufficient to do this:

  Error creating the new pr: "Validation Failed". Is "Public Repo" access enabled for the token?

I've tried giving the token all the rights I could, and the error persisted. Any idea how I could get by a token for an organization I own? If I could find a pointer to get a suitable token, I could take care of documenting and doing everything else.

[chrysn]

Note to self: Here's where the name is changed:

diff --git a/dist/tools/backport_pr/backport_pr.py b/dist/tools/backport_pr/backport_pr.py
index f2f46c13e4..3639ed3578 100755
--- a/dist/tools/backport_pr/backport_pr.py
+++ b/dist/tools/backport_pr/backport_pr.py
@@ -256,7 +256,7 @@ def main():
         for commit in commits:
             bp_repo.git.cherry_pick("-x", commit["sha"])
         # Push to github
-        origin = _find_remote(repo, username, REPO)
+        origin = _find_remote(repo, 'chrysn-pull-requests', REPO)
         print(f"Pushing branch {new_branch} to {origin}")
         if not args.noop:
             push_info = origin.push(f"{new_branch}:{new_branch}")