Add CHANGELOG

Signed-off-by: Tushar Goel <tushar.goel.dav@gmail.com>

Author: TG1999

CHANGELOG.rst

@@ -9,6 +9,12 @@ Version v31.1.0
 - We re-enabled support for the Retiredotnet vulnerabilities advisories importer.
 
 
+Version v31.1.0
+----------------
+
+- We are now ingesting npm advisories data through GitHub API.
+
+
 Version v31.0.0
 ----------------