Update optimization_checks.py

Typo, missed quote.

Author: diegosuarez

internal/optimization_checks.py

@@ -306,7 +306,7 @@ def __init__(self, job, task, requests):
                         '.dsa.dnsv1.com.cn'],
             'Transparent Edge': ['.edge2befaster.io',
                                  '.edge2befaster.net',
-                                 '.edgetcdn.io,
+                                 '.edgetcdn.io',
                                  '.edgetcdn.net'],
             'TRBCDN': ['.trbcdn.net'],
             'Twitter': ['.twimg.com'],