update-nixpkgs: fix manual actions on integration branch and cleanup

We want that users can push to the integration branch and then run the
action. This is the SOP for merge conflict handling. Currently this is
broken as the intergration branch isn't fetched.

Also only delete branches in cleanup that start with the current platform
version.

src/update_nixpkgs/cleanup.py

@@ -76,7 +76,7 @@ def rebase_nixpkgs(
     return True
 
 
-def cleanup_old_prs_and_branches(gh: Github, merged_integration_branch: str):
+def cleanup_old_prs_and_branches(gh: Github, merged_integration_branch: str, platform_branch: str):
     info("Cleaning up old PRs and branches.")
     fc_nixos_repo = gh.get_repo(FC_NIXOS_REPO)
     nixpkgs_repo = gh.get_repo(NIXPKGS_REPO)
@@ -86,7 +86,7 @@ def cleanup_old_prs_and_branches(gh: Github, merged_integration_branch: str):
     # branches will be closed automatically by GitHub, when the branch is deleted
     for repo in [fc_nixos_repo, nixpkgs_repo]:
         for branch in repo.get_branches():
-            if not branch.name.startswith("nixpkgs-auto-update/"):
+            if not branch.name.startswith(f"nixpkgs-auto-update/{platform_branch}/"):
                 continue
             branch_datestr = branch.name.split("/")[2]
             if (
@@ -124,4 +124,4 @@ def run(
         fc_nixos_pr.create_issue_comment(
             f"Rebased nixpkgs `{nixpkgs_target_branch}` branch successfully."
         )
-        cleanup_old_prs_and_branches(gh, integration_branch)
+        cleanup_old_prs_and_branches(gh, integration_branch, fc_nixos_pr.base.ref)

src/update_nixpkgs/update.py

@@ -263,7 +263,7 @@ def run(
             "upstream": Remote(nixpkgs_upstream_url, [nixpkgs_target_branch]),
             "origin": Remote(
                 nixpkgs_origin_url,
-                [nixpkgs_target_branch, last_day_integration_branch],
+                [nixpkgs_target_branch, integration_branch, last_day_integration_branch],
             ),
         }
         nixpkgs_repo = nixpkgs_repository(nixpkgs_dir, remotes)