fix isort installation error

[dorschw]

PyCQA/isort#2077 reproduced on CircleCI

fixes: https://jira-hq.paloaltonetworks.local/browse/CIAC-5455

[coveralls]

Pull Request Test Coverage Report for Build b4003216-95f0-4033-9ba2-a2a983c82980

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 13900 unchanged lines in 165 files lost coverage.
• Overall coverage decreased (-43.5%) to 38.748%

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Files with Coverage Reduction	New Missed Lines	%
demisto_sdk/commands/common/content/errors.py	1	67.24%
demisto_sdk/commands/common/content/objects/abstract_objects/dictionary_based_object.py	1	63.83%
demisto_sdk/commands/common/content/objects/pack_objects/abstract_pack_objects/yaml_content_object.py	1	93.33%
demisto_sdk/commands/common/content/objects/pack_objects/dashboard/dashboard.py	1	83.33%
demisto_sdk/commands/common/content/objects/pack_objects/doc_file/doc_file.py	1	83.33%
demisto_sdk/commands/common/content/objects/pack_objects/job/job.py	1	75.0%
demisto_sdk/commands/common/content/objects/pack_objects/playbook/playbook.py	1	71.43%
demisto_sdk/commands/common/content/objects/pack_objects/report/report.py	1	83.33%
demisto_sdk/commands/common/content/objects/pack_objects/widget/widget.py	1	83.33%
demisto_sdk/commands/common/content/objects/pack_objects/wizard/wizard.py	1	77.78%

Totals
Change from base Build 0b2ab22b-07b4-4602-a9bf-10bc4a379544:	-43.5%
Covered Lines:	12793
Relevant Lines:	33016

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 8de573c2-872f-412b-89ab-bc53d2d4467a

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-1.03%) to 81.198%

---

Totals
Change from base Build 0b2ab22b-07b4-4602-a9bf-10bc4a379544:	-1.03%
Covered Lines:	29051
Relevant Lines:	35778

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💛 - Coveralls