Remove unnecessary global statement

This function *changes* cve_map by calling its pop() method, but it
does not *reassign* cve_map.  Removing this unnecessary statement gets
rid of an error from our flake8 pre-commit linter.

Author: jsf9k

src/cyhy_cvesync/cve_sync.py

@@ -78,7 +78,6 @@ async def process_cve_json(
         metrics = cve.get("cve", {}).get("metrics", {}).keys()
         if metrics & preferred_cvss_metrics_set:
             # Check if the CVE document already exists in the database
-            global cve_map
             async with cve_map_lock:
                 cve_doc = cve_map.pop(cve_id, None)