purge: Update for Highwinds CDN

The code.jquery.com site is no longer via NetDNA/MaxCDN, rather
it is now via Highwinds. Both part of StackPath, but have very
different APIs.

Ref jquery/infrastructure#438.

Author: Krinkle

config-sample.json

@@ -2,8 +2,10 @@
 	"url": "vagrant.codeorigin.jquery.com",
 	"username": "admin",
 	"password": "secret",
-	"cdn": {
-		"consumer_key": "key",
-		"consumer_secret": "secret"
+
+	"highwinds": {
+		"api_url": "https://striketracker.highwinds.com",
+		"api_token": "example_token",
+		"account_hash": "example_hash"
 	}
 }