Update dependency flux to v4

[mend-for-github-com]

This PR contains the following updates:

Package	Type	Update	Change
flux (source)	dependencies	major	2.1.1 -> 4.0.1

By merging this PR, the issue #2 will be automatically resolved and closed:

Severity	CVSS Score	CVE	Reachability
Medium	6.1	CVE-2022-0235
Low	2.6	CVE-2020-15168

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Release Notes

facebook/flux (flux)

v4.0.1

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• Upgrade fbemitter dependency to 3.x

v4.0.0

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• Upgrade fbjs dependency to ^3.x
• Upgrade for Babel 7 compatibility (#​495) (thanks to @​koba04)
• Added React 17 as a peer dependency

v3.1.3

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• Added support for React 16

v3.1.2

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• No meaningful changes.

v3.1.1

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• No meaningful changes.

v3.1.0

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• Dispatcher: Methods register and unregister can once again be called in
  the middle of a dispatch.

v3.0.0

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• FluxMapStore: Removed. It added very little value over FluxReduceStore.
• FluxContainer: Subscriptions are setup in constructor rather than
  componentDidMount
• FluxContainer: Can create containers using stateless functional components
• FluxContainer: Uses functional version of setState
• FluxMixin: Subscriptions are setup in componentWillMount rather than
  componentDidMount
• Dispatcher: Methods register and unregister can not be called in the
  middle of a dispatch
• React added as peer dependency to flux/utils
• Package dist/FluxUtils.js alongside dist/Flux.js

Note: This is marked as a breaking change due to the large number of small
changes in FluxContainer. Depending on how coupled code is to the timing of
componentWillMount, componentDidMount, or setting state synchronously it is
possible that there may be some breakages. Generally it should not be an issue.

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