Use new test environment format for Jest

[RichDom2185]

Description

Actually, this is the expected way to define environments in the current Jest major version. But I think there might be some backwards compatibility of sorts, thus it still ran on Linux CI as well as my Windows. But it wouldn't on my Mac.

Now it does.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Code quality improvements

Checklist

• I have tested this code
• I have updated the documentation

[coveralls]

Pull Request Test Coverage Report for Build 16291864236

Details

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.002%) to 44.619%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
jsdom-env.js	0	1	0.0%

Totals
Change from base Build 16291861472:	-0.002%
Covered Lines:	10111
Relevant Lines:	21225

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💛 - Coveralls

[sayomaki]

LGTM, thanks!