Add missing ESI operation to eveonline swagger spec file.

When I minimized the swagger spec in !1338 (merged) I omitted yet another operation whose use wasn't documented anywhere ^glares - it's back now.

If minimizing swagger specs is no longer in vogue I can stop. It makes a difference in performance, as initializing a bravado client can be slow with large swagger specs.

This may be related to the sudden appearance of errors associated with !1381 (merged) as the missing operation forced the bulk character update task to update models singularly which uses a different ESI operation. Or at least it should have every time. Reports are the task is somehow still working? It shouldn't be.