Shrink the size of the argument to SCMProvider.check_for_update

[tomrittervg]

We don't need the whole job object, just its version is sufficient.

This is an ugly fix for a recursion overflow in the memoize implementation where we pickle the argument.

A better fix would be to fix memoize.
Or revisit the need to have a linked list of every single job for a library.

Fixes #403

[mozfreddyb]

 Error:   (None dav1d job_id=1) Caught an exception while processing library dav1d task type vendoring
Traceback (most recent call last):
  File "/home/runner/work/updatebot/updatebot/automation.py", line 233, in run
    taskRunner.process_task(lib, task)
  File "/home/runner/work/updatebot/updatebot/tasktypes/vendoring.py", line 79, in process_task
    self._process_new_job(library, task, new_version, timestamp, most_recent_job)
  File "/home/runner/work/updatebot/updatebot/components/logging.py", line 38, in func_wrapper
    ret = func(*args, **kwargs)
  File "/home/runner/work/updatebot/updatebot/tasktypes/vendoring.py", line 133, in _process_new_job
    all_upstream_commits, unseen_upstream_commits = self.scmProvider.check_for_update(library, task, new_version, most_recent_job.version)
AttributeError: 'NoneType' object has no attribute 'version'

Looks like you didn't catch all code when refactoring.

[mozfreddyb]

Approving such that this is unblocked from landing. There's an outstanding refactoring left as you can see from CI failure though.