Added source and severity_modification_type filters to vm export (#738)

* added new filters to vm export, fixed snyk issue

* edited the documentation from asset to scan

tenable/io/exports/api.py

@@ -399,6 +399,10 @@ def vulns(self, **kwargs) -> Union[ExportsIterator, UUID]:
                 Only return findings with the specified plugin type.
             scan_uuid (uuid, optional):
                 Only return findings with the specified scan UUID.
+            source (list[str], optional):
+                Only return vulnerabilities for assets that have the specified scan source.
+            severity_modification_type (list[str], optional):
+                Only return vulnerabilities with the specified severity modification type.
             severity (list[str], optional):
                 Only return findings with the specified severities.
             state (list[str], optional):

tenable/io/exports/schema.py

@@ -86,6 +86,8 @@ class VulnExportSchema(Schema):
     state = fields.List(LowerCase(fields.Str()))
     vpr_score = fields.Nested(VPRSchema())
     scan_uuid = fields.Str()
+    source = fields.List(fields.Str())
+    severity_modification_type = fields.List(fields.Str())
 
     # Asset fields
     tags = fields.List(fields.Tuple((fields.Str(), fields.Str())))