Update docker to 4.4.4

[pyup-bot]

This PR updates docker from 4.3.1 to 4.4.4.

Changelog

4.4.4

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[List of PRs / issues for this release](https://github.com/docker/docker-py/milestone/73?closed=1)

Bugfixes
- Remove `LD_LIBRARY_PATH` and `SSL_CERT_FILE` environment variables when shelling out to the ssh client

4.4.3

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[List of PRs / issues for this release](https://github.com/docker/docker-py/milestone/72?closed=1)

Features
- Add support for docker.types.Placement.MaxReplicas

Bugfixes
- Fix SSH port parsing when shelling out to the ssh client

4.4.2

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[List of PRs / issues for this release](https://github.com/docker/docker-py/milestone/71?closed=1)

Bugfixes
- Fix SSH connection bug where the hostname was incorrectly trimmed and the error was hidden
- Fix docs example

Miscellaneous
- Add Python3.8 and 3.9 in setup.py classifier list

4.4.1

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[List of PRs / issues for this release](https://github.com/docker/docker-py/milestone/69?closed=1)

Bugfixes
- Avoid setting unsuported parameter for subprocess.Popen on Windows
- Replace use of deprecated "filter" argument on ""docker/api/image"

4.4.0

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[List of PRs / issues for this release](https://github.com/docker/docker-py/milestone/67?closed=1)

Features
- Add an alternative SSH connection to the paramiko one, based on shelling out to the SSh client. Similar to the behaviour of Docker cli
- Default image tag to `latest` on `pull`

Bugfixes
- Fix plugin model upgrade
- Fix examples URL in ulimits

Miscellaneous
- Improve exception messages for server and client errors
- Bump cryptography from 2.3 to 3.2

Links

• PyPI: https://pypi.org/project/docker
• Changelog: https://pyup.io/changelogs/docker/
• Repo: https://github.com/docker/docker-py

[pyup-bot]

Closing this in favor of #444