diff --git a/vendor/github.com/jhump/protoreflect/dynamic/maps_1.11.go b/vendor/github.com/jhump/protoreflect/dynamic/maps_1.11.go
new file mode 100644
index 0000000..bb68d7b
--- /dev/null
+++ b/vendor/github.com/jhump/protoreflect/dynamic/maps_1.11.go
@@ -0,0 +1,129 @@
+//+build !go1.12
+
+package dynamic
+
+import (
+	"github.com/jhump/protoreflect/desc"
+	"reflect"
+)
+
+// Pre-Go-1.12, we must use reflect.Value.MapKeys to reflectively
+// iterate a map. (We can be more efficient in Go 1.12 and up...)
+
+func mapsEqual(a, b reflect.Value) bool {
+	if a.Len() != b.Len() {
+		return false
+	}
+	if a.Len() == 0 && b.Len() == 0 {
+		// Optimize the case where maps are frequently empty because MapKeys()
+		// function allocates heavily.
+		return true
+	}
+
+	for _, k := range a.MapKeys() {
+		av := a.MapIndex(k)
+		bv := b.MapIndex(k)
+		if !bv.IsValid() {
+			return false
+		}
+		if !fieldsEqual(av.Interface(), bv.Interface()) {
+			return false
+		}
+	}
+	return true
+}
+
+func validFieldValueForMapField(fd *desc.FieldDescriptor, val reflect.Value) (interface{}, error) {
+	// make a defensive copy while we check the contents
+	// (also converts to map[interface{}]interface{} if it's some other type)
+	keyField := fd.GetMessageType().GetFields()[0]
+	valField := fd.GetMessageType().GetFields()[1]
+	m := map[interface{}]interface{}{}
+	for _, k := range val.MapKeys() {
+		if k.Kind() == reflect.Interface {
+			// unwrap it
+			k = reflect.ValueOf(k.Interface())
+		}
+		kk, err := validFieldValueForRv(keyField, k)
+		if err != nil {
+			return nil, err
+		}
+		v := val.MapIndex(k)
+		if v.Kind() == reflect.Interface {
+			// unwrap it
+			v = reflect.ValueOf(v.Interface())
+		}
+		vv, err := validFieldValueForRv(valField, v)
+		if err != nil {
+			return nil, err
+		}
+		m[kk] = vv
+	}
+	return m, nil
+}
+
+func canConvertMap(src reflect.Value, target reflect.Type) bool {
+	kt := target.Key()
+	vt := target.Elem()
+	for _, k := range src.MapKeys() {
+		if !canConvert(k, kt) {
+			return false
+		}
+		if !canConvert(src.MapIndex(k), vt) {
+			return false
+		}
+	}
+	return true
+}
+
+func mergeMapVal(src, target reflect.Value, targetType reflect.Type) error {
+	tkt := targetType.Key()
+	tvt := targetType.Elem()
+	for _, k := range src.MapKeys() {
+		v := src.MapIndex(k)
+		skt := k.Type()
+		svt := v.Type()
+		var nk, nv reflect.Value
+		if tkt == skt {
+			nk = k
+		} else if tkt.Kind() == reflect.Ptr && tkt.Elem() == skt {
+			nk = k.Addr()
+		} else {
+			nk = reflect.New(tkt).Elem()
+			if err := mergeVal(k, nk); err != nil {
+				return err
+			}
+		}
+		if tvt == svt {
+			nv = v
+		} else if tvt.Kind() == reflect.Ptr && tvt.Elem() == svt {
+			nv = v.Addr()
+		} else {
+			nv = reflect.New(tvt).Elem()
+			if err := mergeVal(v, nv); err != nil {
+				return err
+			}
+		}
+		if target.IsNil() {
+			target.Set(reflect.MakeMap(targetType))
+		}
+		target.SetMapIndex(nk, nv)
+	}
+	return nil
+}
+
+func mergeMapField(m *Message, fd *desc.FieldDescriptor, rv reflect.Value) error {
+	for _, k := range rv.MapKeys() {
+		if k.Kind() == reflect.Interface && !k.IsNil() {
+			k = k.Elem()
+		}
+		v := rv.MapIndex(k)
+		if v.Kind() == reflect.Interface && !v.IsNil() {
+			v = v.Elem()
+		}
+		if err := m.putMapField(fd, k.Interface(), v.Interface()); err != nil {
+			return err
+		}
+	}
+	return nil
+}