`av==10.0.0` breaks CI

[pmeier]

The recent release of av==10.0.0 breaks at least two tests: https://app.circleci.com/pipelines/github/pytorch/vision/21245/workflows/ecbc81ff-f864-4227-a35d-b4ed5e9f57ee/jobs/1724114?invite=true#step-108-3075

=================================== FAILURES ===================================
____________________ TestVideo.test_video_clips_custom_fps _____________________
Traceback (most recent call last):
  File "/root/project/env/lib/python3.7/site-packages/torch/utils/data/dataloader.py", line 1120, in _try_get_data
    data = self._data_queue.get(timeout=timeout)
  File "/root/project/env/lib/python3.7/multiprocessing/queues.py", line 104, in get
    if not self._poll(timeout):
  File "/root/project/env/lib/python3.7/multiprocessing/connection.py", line 257, in poll
    return self._poll(timeout)
  File "/root/project/env/lib/python3.7/multiprocessing/connection.py", line 414, in _poll
    r = wait([self], timeout)
  File "/root/project/env/lib/python3.7/multiprocessing/connection.py", line 921, in wait
    ready = selector.select(timeout)
  File "/root/project/env/lib/python3.7/selectors.py", line 415, in select
    fd_event_list = self._selector.poll(timeout)
  File "/root/project/env/lib/python3.7/site-packages/torch/utils/data/_utils/signal_handling.py", line 66, in handler
    _error_if_any_worker_fails()
RuntimeError: DataLoader worker (pid 5231) is killed by signal: Segmentation fault. 

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/root/project/test/test_datasets_video_utils.py", line 63, in test_video_clips_custom_fps
    video_clips = VideoClips(video_list, num_frames, num_frames, fps, num_workers=2)
  File "/root/project/torchvision/datasets/video_utils.py", line 132, in __init__
    self._compute_frame_pts()
  File "/root/project/torchvision/datasets/video_utils.py", line 153, in _compute_frame_pts
    for batch in dl:
  File "/root/project/env/lib/python3.7/site-packages/torch/utils/data/dataloader.py", line 628, in __next__
    data = self._next_data()
  File "/root/project/env/lib/python3.7/site-packages/torch/utils/data/dataloader.py", line 1316, in _next_data
    idx, data = self._get_data()
  File "/root/project/env/lib/python3.7/site-packages/torch/utils/data/dataloader.py", line 1282, in _get_data
    success, data = self._try_get_data()
  File "/root/project/env/lib/python3.7/site-packages/torch/utils/data/dataloader.py", line 1133, in _try_get_data
    raise RuntimeError('DataLoader worker (pid(s) {}) exited unexpectedly'.format(pids_str)) from e
RuntimeError: DataLoader worker (pid(s) 5231) exited unexpectedly
----------------------------- Captured stderr call -----------------------------
100.0%
ERROR: Unexpected segmentation fault encountered in worker.
ERROR: Unexpected segmentation fault encountered in worker.

I'm going to pin to < 10.

cc @seemethere

[pmeier]

#6814 includes reproduction

[bjuncek]

@pmeier I'll close this as #6814 contains repro, and seems to have been fixed in here.
I'll double check to see if the mentioned fix also fixes the CI locally and add the rest of the info to that issue