Update to flutter 3.22.2 and intl 0.19.0

Description

Updates dependencies

Related issues & PRs

n/a

Checklist

[x] I have made myself familiar with the CaTeX contributing guide.
[x] I added a PR description.
[x] I linked all related issues and PRs I could find (no links if there are none).
[x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
[x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
[x] If there is new functionality in code, I added tests covering all my additions.
[x] All required checks pass.

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Project coverage is 27.11%. Comparing base (3a9a76e) to head (415ae7b).

:exclamation: Current head 415ae7b differs from pull request most recent head a25601c

Please upload reports for the commit a25601c to get more accurate results.

Files	Patch %	Lines
math_keyboard/lib/src/widgets/math_field.dart	0.00%	6 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #67 +/- ## ======================================= Coverage 27.11% 27.11% ======================================= Files 11 11 Lines 1147 1147 ======================================= Hits 311 311 Misses 836 836 ``` | [Flag](https://app.codecov.io/gh/simpleclub/math_keyboard/pull/67/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=simpleclub) | Coverage Δ | | |---|---|---| | [math_keyboard](https://app.codecov.io/gh/simpleclub/math_keyboard/pull/67/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=simpleclub) | `27.11% <0.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=simpleclub#carryforward-flags-in-the-pull-request-comment) to find out more.

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simpleclub / math_keyboard