Dependency on a non-existent datetime.time service

Hmm... the error still occurs on the 8.x-1.x branch. I'm not sure how this change could've caused it, since it's on /admin/tmgmt/jobs, which directly goes to ContinuousJobForm which inherits TmgmtFormBase::create, and that's where the datetime.time service is requested. The plugins don't seem to be touched at that point...

The actual commit that broke it seems to be 691bbcc1 in #2840331: Missing parent call in TmgmtFormBase::__constuctor. Your parent::__construct call targets the 8.3.x version of ContentEntityForm:

  /**
   * Constructs a ContentEntityForm object.
   *
   * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
   *   The entity manager.
   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
   *   The entity type bundle service.
   * @param \Drupal\Component\Datetime\TimeInterface $time
   *   The time service.
   */
  public function __construct(EntityManagerInterface $entity_manager, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, TimeInterface $time = NULL) {
    $this->entityManager = $entity_manager;

    $this->entityTypeBundleInfo = $entity_type_bundle_info ?: \Drupal::service('entity_type.bundle.info');
    $this->time = $time ?: \Drupal::service('datetime.time');
  }

The 8.2.5 version only takes the EMI:

  /**
   * Constructs a ContentEntityForm object.
   *
   * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
   *   The entity manager.
   */
  public function __construct(EntityManagerInterface $entity_manager) {
    $this->entityManager = $entity_manager;
  }

(I can confirm that after reverting 691bbcc1, the /admin/tmgmt/jobs page works correctly.)

This removes the two extra arguments to bring the code in line with 8.2.5. :)