Update AWS lambda for the 3.4.3.13 release (#69)

schemas/aws-lambda/3.4.x.json

@@ -80,6 +80,12 @@
               "type": "string"
             }
           },
+          {
+            "aws_sts_endpoint_url": {
+              "description": "A string representing a URL, such as https://example.com/path/to/resource?q=search.",
+              "type": "string"
+            }
+          },
           {
             "aws_region": {
               "type": "string",
@@ -252,4 +258,4 @@
       }
     }
   ]
-}
+}