Method convertJsonPointerIntoPropertyPath() does not exist in class JsonSchema\Constraints\BaseConstraint

[emmanuelGuiton]

The class JsonSchema\Constraints\BaseConstraint uses a method convertJsonPointerIntoPropertyPath() that is not defined though the class is not abstract and it does not extend any other.
See https://github.com/justinrainbow/json-schema/blob/f4f0c3457811006f861c466a10c6c24f3e92f9ae/src/JsonSchema/Constraints/BaseConstraint.php#L52

Thus, using the addError method on a JsonSchema\Validator instance throws an error :

php > require_once "target/vendor/autoload.php";
php > $validator = new JsonSchema\Validator();
php > $validator->addError(null,'An error message.');
PHP Warning:  Uncaught Error: Call to undefined method JsonSchema\Validator::convertJsonPointerIntoPropertyPath() in /home/nanu/git/rtms/libraries/core/target/vendor/justinrainbow/json-schema/src/JsonSchema/Constraints/BaseConstraint.php:49
Stack trace:
#0 php shell code(1): JsonSchema\Constraints\BaseConstraint->addError()
#1 {main}
  thrown in /home/nanu/git/rtms/libraries/core/target/vendor/justinrainbow/json-schema/src/JsonSchema/Constraints/BaseConstraint.php on line 49

Note that the convertJsonPointerIntoPropertyPath() method is defined in the JsonSchema\Constraints\Constraint abstract class. The latter extends JsonSchema\Constraints\BaseConstraint. Moving the method in this class solves the issue.