create-branches: Add a delay in the hope that no pipeline is created

Try to give more time to GitLab to realize we created a new branch so
hopefully it will stop creating pipelines for it.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

release-scripts/create-branches

@@ -7,10 +7,12 @@ import collections.abc
 import concurrent.futures
 import fnmatch
 import logging
+import time
 import sys
 
 import gitlab
 
+BRANCH_CREATION_SLEEP_SECONDS = 20
 
 def item_id(item):
     itemid = None
@@ -105,6 +107,12 @@ def _create_branch(project, base_branch, new_branch, really):
         project.default_branch = new_branch
         if really:
             project.save()
+            # when creating many branches at the same time GitLab may need some time to realize
+            # if we re-enable the CI too soon, it will still create pipelines for the new refs
+            logging.info(
+                f"{project.path_with_namespace}: Sleeping for {BRANCH_CREATION_SLEEP_SECONDS}s to let GitLab realize {new_branch} has been created"
+            )
+            time.sleep(BRANCH_CREATION_SLEEP_SECONDS)
     finally:
         logging.info(
             f"{project.path_with_namespace}: Restoring CI settings to {original_builds_access_level}"
@@ -158,7 +166,7 @@ class Brancher:
 
     def branch(self, branch_prefix, base_release, new_release, really):
         logging.info(f"Branching {new_release} from {base_release}")
-        num_worker_threads = 10
+        num_worker_threads = 30
         branch_prefix = branch_prefix.rstrip("/") + "/"
         base_branch = branch_prefix + base_release
         new_branch = branch_prefix + new_release