Change DTLS default from 1.0 to 1.2 for webrtc.

webrtc/base/sslstreamadapterhelper.cc

Index: webrtc/base/sslstreamadapterhelper.cc
diff --git a/webrtc/base/sslstreamadapterhelper.cc b/webrtc/base/sslstreamadapterhelper.cc
index c3be4ea6845456b46fdbc1ea111affd49f2a2eef..61c0e43ff78d56ef0c739328ba4c947a144839fd 100644
--- a/webrtc/base/sslstreamadapterhelper.cc
+++ b/webrtc/base/sslstreamadapterhelper.cc
@@ -29,8 +29,7 @@ SSLStreamAdapterHelper::SSLStreamAdapterHelper(StreamInterface* stream)
       role_(SSL_CLIENT),
       ssl_error_code_(0),  // Not meaningful yet
       ssl_mode_(SSL_MODE_TLS),
-      ssl_max_version_(SSL_PROTOCOL_TLS_11) {
-}
+      ssl_max_version_(SSL_PROTOCOL_TLS_12) {}
 
 SSLStreamAdapterHelper::~SSLStreamAdapterHelper() = default;