Remove NPM importer's migrations, rely on importer_yielder.py instead

Signed-off-by: Shivam Sandbhor <shivam.sandbhor@gmail.com>

Author: sbs2001

vulnerabilities/importer_yielder.py

@@ -75,7 +75,9 @@
         'license': '',
         'last_run': None,
         'data_source': 'NpmDataSource',
-        'data_source_cfg': {},
+        'data_source_cfg': {
+            'repository_url': 'https://github.com/nodejs/security-wg.git'
+        },
     },
     {
         'name': 'ruby',