Update dependencies (#1784)

vendor/github.com/mattermost/mattermost-server/v6/model/utils.go

@@ -132,6 +132,24 @@ func (m StringMap) Value() (driver.Value, error) {
 	return string(j), err
 }
 
+func (StringMap) ImplementsGraphQLType(name string) bool {
+	return name == "StringMap"
+}
+
+func (m StringMap) MarshalJSON() ([]byte, error) {
+	return json.Marshal((map[string]string)(m))
+}
+
+func (m *StringMap) UnmarshalGraphQL(input interface{}) error {
+	json, ok := input.(map[string]string)
+	if !ok {
+		return errors.New("wrong type")
+	}
+
+	*m = json
+	return nil
+}
+
 func (si *StringInterface) Scan(value interface{}) error {
 	if value == nil {
 		return nil