Update dependency flask to v2

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
flask (changelog)	==1.1.4 -> ==2.0.1

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Configuration

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[coveralls]

Pull Request Test Coverage Report for Build 989603586

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.005%) to 94.966%

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Totals
Change from base Build 989601979:	0.005%
Covered Lines:	849
Relevant Lines:	894

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💛 - Coveralls