Upgrade intl to 0.19.0 AND gradle from 4.2.2 to 7.4.2

[jhaglund]

Connection with issue(s)

Close #90
Close #91 Close #92 Close #93

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Solution description

(updated May 17 to try to be more clear) You're welcome to replicate the steps I did. The only "manual" edit I did was to change the 18 to 19, otherwise the changes were all made by the Android Studio tools.

The key is instead of opening the Flutter project, you open the /example/android directory with Android Studio then use the AGP upgrade assistant (under tools) to upgrade gradle. Maybe VS code can do it but IDK. Sorry I made so many commits, this process gets sticky so I was cribbing my progress.

Thanks!

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