Refactor: update to latest Flutter version

[TesteurManiak]

No description provided.

[Pierre-Monier]

LGTM

[coveralls]

Pull Request Test Coverage Report for Build 7279357670

• 8 of 247 (3.24%) changed or added relevant lines in 12 files are covered.
• 18 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-9.0%) to 75.464%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/src/components/accordion/programmable_expansion_tile.dart	2	3	66.67%
lib/src/fonts.dart	0	1	0.0%
lib/src/theme/button_style.dart	0	12	0.0%
lib/src/theme/radius.dart	1	13	7.69%
lib/src/theme/theme_data.dart	0	20	0.0%
lib/src/theme/typography.dart	0	26	0.0%
lib/src/theme/sizes.dart	0	38	0.0%
lib/src/theme/spacings.dart	0	40	0.0%
lib/src/theme/colors.dart	0	89	0.0%

Files with Coverage Reduction	New Missed Lines	%
lib/src/theme/sizes.dart	18	2.08%

Totals
Change from base Build 3595161557:	-9.0%
Covered Lines:	1830
Relevant Lines:	2425

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💛 - Coveralls