Dep upgrade mysql lib (#4161)

*  update gopkg file to add sql dep

vendor/github.com/go-sql-driver/mysql/const.go

@@ -9,7 +9,9 @@
 package mysql
 
 const (
-	minProtocolVersion byte = 10
+	defaultAuthPlugin       = "mysql_native_password"
+	defaultMaxAllowedPacket = 4 << 20 // 4 MiB
+	minProtocolVersion      = 10
 	maxPacketSize           = 1<<24 - 1
 	timeFormat              = "2006-01-02 15:04:05.999999"
 )
@@ -18,10 +20,11 @@ const (
 // http://dev.mysql.com/doc/internals/en/client-server-protocol.html
 
 const (
-	iOK          byte = 0x00
-	iLocalInFile byte = 0xfb
-	iEOF         byte = 0xfe
-	iERR         byte = 0xff
+	iOK           byte = 0x00
+	iAuthMoreData byte = 0x01
+	iLocalInFile  byte = 0xfb
+	iEOF          byte = 0xfe
+	iERR          byte = 0xff
 )
 
 // https://dev.mysql.com/doc/internals/en/capability-flags.html#packet-Protocol::CapabilityFlags
@@ -87,8 +90,10 @@ const (
 )
 
 // https://dev.mysql.com/doc/internals/en/com-query-response.html#packet-Protocol::ColumnType
+type fieldType byte
+
 const (
-	fieldTypeDecimal byte = iota
+	fieldTypeDecimal fieldType = iota
 	fieldTypeTiny
 	fieldTypeShort
 	fieldTypeLong
@@ -107,7 +112,7 @@ const (
 	fieldTypeBit
 )
 const (
-	fieldTypeJSON byte = iota + 0xf5
+	fieldTypeJSON fieldType = iota + 0xf5
 	fieldTypeNewDecimal
 	fieldTypeEnum
 	fieldTypeSet
@@ -161,3 +166,9 @@ const (
 	statusInTransReadonly
 	statusSessionStateChanged
 )
+
+const (
+	cachingSha2PasswordRequestPublicKey          = 2
+	cachingSha2PasswordFastAuthSuccess           = 3
+	cachingSha2PasswordPerformFullAuthentication = 4
+)