ARROW-12327: [Dev] Use pull request's head remote when submitting crossbow jobs via the comment bot

Closes #9978 from kszucs/crossbow-remote

Authored-by: Krisztián Szűcs <szucs.krisztian@gmail.com>
Signed-off-by: Krisztián Szűcs <szucs.krisztian@gmail.com>
diff --git a/dev/archery/archery/bot.py b/dev/archery/archery/bot.py
index 35b69a6..27cf247 100644
--- a/dev/archery/archery/bot.py
+++ b/dev/archery/archery/bot.py
@@ -240,7 +240,8 @@
 
         # initialize the crossbow build's target repository
         target = Target.from_repo(arrow, version=arrow_version,
-                                  remote=pull_request.base.repo.clone_url)
+                                  remote=pull_request.head.repo.clone_url,
+                                  branch=pull_request.head.ref)
 
         # parse additional job parameters
         params = dict([p.split("=") for p in params])