support/scripts/pkg-stats: fix flake8 errors

support/scripts/pkg-stats:1171:8: E713 test for membership should be 'not in'
support/scripts/pkg-stats:1175:8: E713 test for membership should be 'not in'
support/scripts/pkg-stats:1179:8: E713 test for membership should be 'not in'
3     E713 test for membership should be 'not in'

Fixes: https://gitlab.com/buildroot.org/buildroot/-/jobs/1955772278

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

support/scripts/pkg-stats

@@ -1168,15 +1168,15 @@ def __main__():
         pkg.set_url()
         pkg.set_ignored_cves()
         pkg.set_developers(developers)
-    if not "url" in args.disable:
+    if "url" not in args.disable:
         print("Checking URL status")
         loop = asyncio.get_event_loop()
         loop.run_until_complete(check_package_urls(packages))
-    if not "upstream" in args.disable:
+    if "upstream" not in args.disable:
         print("Getting latest versions ...")
         loop = asyncio.get_event_loop()
         loop.run_until_complete(check_package_latest_version(packages))
-    if not "cve" in args.disable and args.nvd_path:
+    if "cve" not in args.disable and args.nvd_path:
         print("Checking packages CVEs")
         check_package_cves(args.nvd_path, packages)
         check_package_cpes(args.nvd_path, packages)