The upstream didn't merge kkroening/ffmpeg-python#330

This sets up GitHub Actions (GHA) to run in place of the
currently broken Travis CI.  Initially, this only covers running
tox/pytest and Black, but may eventually be extended to run pylint,
mypy, flake8, etc. - see #605, for example.

Notes:
* Python 3.10 is not yet supported due to the `collections.Iterable`
  issue discussed in #330, #624, etc.
* The Black CI step acts as a linting step, rather than attempting to
  have the GHA job automatically update/commit/push the reformarted
  code.
* Black is currently pinned to an older version that supports
  `--target-version py27` until Python 2 compatibility can be dropped in
  the final Python 2 compatibility release of ffmpeg-python.
* Only the main source directory (`ffmpeg/`) is checked with Black at
  the moment.  The `examples/` directory should also be checked, but
  will be done as a separate PR.

This sets up GitHub Actions (GHA) to run in place of the
currently broken Travis CI.  Initially, this only covers running
tox/pytest and Black, but may eventually be extended to run pylint,
mypy, flake8, etc. - see #605, for example.

Notes:
* Python 3.10 is not yet supported due to the `collections.Iterable`
  issue discussed in #330, #624, etc.
* The Black CI step acts as a linting step, rather than attempting to
  have the GHA job automatically update/commit/push the reformarted
  code.
* Black is currently pinned to an older version that supports
  `--target-version py27` until Python 2 compatibility can be dropped in
  the final Python 2 compatibility release of ffmpeg-python.
* Only the main source directory (`ffmpeg/`) is checked with Black at
  the moment.  The `examples/` directory should also be checked, but
  will be done as a separate PR.

This sets up GitHub Actions (GHA) to run in place of the
currently broken Travis CI.  Initially, this only covers running
tox/pytest and Black, but may eventually be extended to run pylint,
mypy, flake8, etc. - see #605, for example.

Notes:
* Python 3.10 is not yet supported due to the `collections.Iterable`
  issue discussed in #330, #624, etc.
* The Black CI step acts as a linting step, rather than attempting to
  have the GHA job automatically update/commit/push the reformarted
  code.
* Black is currently pinned to an older version that supports
  `--target-version py27` until Python 2 compatibility can be dropped in
  the final Python 2 compatibility release of ffmpeg-python.
* Only the main source directory (`ffmpeg/`) is checked with Black at
  the moment.  The `examples/` directory should also be checked, but
  will be done as a separate PR.

This sets up GitHub Actions (GHA) to run in place of the
currently broken Travis CI.  Initially, this only covers running
tox/pytest and Black, but may eventually be extended to run pylint,
mypy, flake8, etc. - see #605, for example.

Notes:
* Python 3.10 is not yet supported due to the `collections.Iterable`
  issue discussed in #330, #624, etc.
* The Black CI step acts as a linting step, rather than attempting to
  have the GHA job automatically update/commit/push the reformarted
  code.
* Black is currently pinned to an older version that supports
  `--target-version py27` until Python 2 compatibility can be dropped in
  the final Python 2 compatibility release of ffmpeg-python.
* Only the main source directory (`ffmpeg/`) is checked with Black at
  the moment.  The `examples/` directory should also be checked, but
  will be done as a separate PR.

This sets up GitHub Actions (GHA) to run in place of the
currently broken Travis CI.  Initially, this only covers running
tox/pytest and Black, but may eventually be extended to run pylint,
mypy, flake8, etc. - see #605, for example.

Notes:
* Python 3.10 is not yet supported due to the `collections.Iterable`
  issue discussed in #330, #624, etc.
* The Black CI step acts as a linting step, rather than attempting to
  have the GHA job automatically update/commit/push the reformarted
  code.
* Black is currently pinned to an older version that supports
  `--target-version py27` until Python 2 compatibility can be dropped in
  the final Python 2 compatibility release of ffmpeg-python.
* Only the main source directory (`ffmpeg/`) is checked with Black at
  the moment.  The `examples/` directory should also be checked, but
  will be done as a separate PR.

Co-authored by: Christian Clauss <cclauss@me.com>