Update go dependencies

vendor/go.opencensus.io/stats/measure_float64.go

@@ -17,13 +17,17 @@ package stats
 
 // Float64Measure is a measure for float64 values.
 type Float64Measure struct {
-	*measureDescriptor
+	desc *measureDescriptor
 }
 
 // M creates a new float64 measurement.
 // Use Record to record measurements.
 func (m *Float64Measure) M(v float64) Measurement {
-	return Measurement{m: m.measureDescriptor, v: v}
+	return Measurement{
+		m:    m,
+		desc: m.desc,
+		v:    v,
+	}
 }
 
 // Float64 creates a new measure for float64 values.
@@ -34,3 +38,18 @@ func Float64(name, description, unit string) *Float64Measure {
 	mi := registerMeasureHandle(name, description, unit)
 	return &Float64Measure{mi}
 }
+
+// Name returns the name of the measure.
+func (m *Float64Measure) Name() string {
+	return m.desc.name
+}
+
+// Description returns the description of the measure.
+func (m *Float64Measure) Description() string {
+	return m.desc.description
+}
+
+// Unit returns the unit of the measure.
+func (m *Float64Measure) Unit() string {
+	return m.desc.unit
+}