Merge pull request #70 from earth2marsh/patch-2

Updating vendorExtension description to new pattern

Author: fehguy

schemas/v2.0/schema.json

@@ -161,7 +161,7 @@
 			"additionalProperties": false
 		},
 		"vendorExtension": {
-			"description": "Any property starting with _ is valid.",
+			"description": "Any property starting with x- is valid.",
 			"additionalProperties": true,
 			"additionalItems": true
 		},