Build failing: Referenced sniff does not exist

[dafeder]

I reported codeclimate/codeclimate-phpcodesniffer#93 but given that I can get the same test running on the local CLI perhaps this is the right place for this? All of our builds are failing with the error Referenced sniff "SlevomatCodingStandard.ControlStructures.RequireNullCoalesceOperator" does not exist.

Here is a failing build:

https://codeclimate.com/github/GetDKAN/dkan/builds/2781

We're using only the phpcodesniffer plugin (beta channel), using the Drupal and DrupalPractice standards. Here is the .codeclimate.yml from that particular build.

The full stack trace from the build:

Exception: ERROR: Referenced sniff "SlevomatCodingStandard.ControlStructures.RequireNullCoalesceOperator" does not exist

Run "phpcs --help" for usage information

 in /usr/src/app/vendor/squizlabs/php_codesniffer/src/Runner.php
#0 /usr/src/app/Executor.php(116): PHP_CodeSniffer\Runner->init()
#1 /usr/src/app/vendor/barracudanetworks/forkdaemon-php/fork_daemon.php(1934): Executor->run()
#2 /usr/src/app/vendor/barracudanetworks/forkdaemon-php/fork_daemon.php(1846): fork_daemon->invoke_callback()
#3 /usr/src/app/vendor/barracudanetworks/forkdaemon-php/fork_daemon.php(1747): fork_daemon->fork_work_unit()
#4 /usr/src/app/vendor/barracudanetworks/forkdaemon-php/fork_daemon.php(1499): fork_daemon->process_work_unit()
#5 /usr/src/app/Executor.php(33): fork_daemon->process_work()
#6 /usr/src/app/engine.php(26): Executor->queueDirectory()
#7 {main}Exception: ERROR: Referenced sniff "SlevomatCodingStandard.ControlStructures.RequireNullCoalesceOperator" does not exist