Update XMPPCertPins.java

Add support for TLSv1.2:
ECDHE-RSA-AES256-GCM-SHA384 (0xc030)
ECDHE-RSA-AES256-SHA384 (0xc028)
DHE-RSA-AES256-GCM-SHA384 (0x9f)
DHE-RSA-AES256-SHA256 (0x6b)