Reduce Pyxis query size from 50 to 20 repositories

Pyxis occasionally fails to handle queries with 50 repositories in the
filter, likely due to database growth. Reducing the chunk size to 20
to improve query reliability.

Author: qixiang

freshmaker/image.py

@@ -1073,7 +1073,7 @@ def find_images_with_packages_from_content_set(
             images = []
             # Split the repos to small chunks to generate "small" queries
             repos_iterator = iter(repos)
-            chunk_size = 50
+            chunk_size = 20
             for i in range(0, len(repos), chunk_size):
                 repos_chunk = {k: repos[k] for k in islice(repos_iterator, chunk_size)}
                 images_chunk = self.find_images_with_included_rpms(