fetch-downstream: Increase parallelism retrieving component

Add more parallel workers whe retrieving the component and licensing
report from git to speed up the process.

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

bin/packaging-data-fetch-downstream

@@ -152,7 +152,7 @@ class DownstreamFetcher:
                 branch.tags.sort()
 
     def fetch_component_license_report(self, projects):
-        num_worker_threads = 10
+        num_worker_threads = 30
 
         def _fetch_license_report(project):
             for branch in project.branches.values():