Fixed CVAT docker image build.

[azhavoro]

Fixed CVAT docker image build.
resolve #1851

Motivation and context

Installation of python-ldap package is failed with setuptools 48.x and 49.0.x

How has this been tested?

CI

Checklist

• I submit my changes into the develop branch
• I have added description of my changes into CHANGELOG file
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (read github docs)
• I have increased versions of npm packages if it is necessary (cvat-canvas,
  cvat-core, cvat-data and cvat-ui)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.
• I have updated the license header for each file (see an example below)

# Copyright (C) 2020 Intel Corporation
#
# SPDX-License-Identifier: MIT

[coveralls]

Pull Request Test Coverage Report for Build 6336

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.004%) to 65.214%

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Totals
Change from base Build 6331:	0.004%
Covered Lines:	11063
Relevant Lines:	16556

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💛 - Coveralls