[4.2.0] - Big update

This update fixes important bugs as well as integrates with Navigator 2. It also adds GetRouterOutlet, similar to angular RouterOutlet thanks to @ahmednfwela. Also, the documentation translation for Vietnamese (@khangahs) has been added, making the GetX documentation available for 11 different languages, which is just fantastic for any opensource project. GetX has achieved more than 5.4k likes from the pub, and more than 4k stars on github, has videos about it with 48k on youtube, and has communities in the 4 hemispheres of the earth, besides having a large list of contributors as you see bellow. We're all happy to facilitate development with dart and flutter, and that making programming hassle-free has been taken around the world.

Changes in this version:

• Fix: Navigating to the same page with Get.offNamed does not delete the controller from that page using Get.lazyPut.

• Fix Readme GetMiddleware typos by @nivisi

• Fix url replace error by @KevinZhang19870314

• Changed response default encoding from latin1 to utf8 by @heftekharm

• Add Duration in ExtensionBottomSheet by @chanonpingpong

• Added compatibility with dart-lang/mockito by @lifez

• Added extensions methods to convert value in percent value by @kauemurakami

• Set darkTheme equal theme when darkTheme is null by @eduardoFlorence

• Add padding to 'defaultDialog' by @KevinZhang19870314

• GraphQLResponse inherit Response info by @jasonlaw

• Fix Redundant concatenating base url by @jasonlaw

• Add content type and length into the headers when the content type is 'application/x-www-form-urlencoded' by @calvingit

• Make withCredentials configurable by @jasonlaw

• Fix flutter 2.0 error by @yunchiri

• Allow deleting all registered instances by @lemps

• Refactor/rx interface notify children @by kranfix

• Fixed parameter parsing and middleware sorting by @ahmednfwela

• Improvements to router outlet by @ahmednfwela

• Minor improvements and bug fixes by @ahmednfwela

• Adding route guards and improving navigation by @ahmednfwela

• Fix RxInterface.proxy losing its previous value on exception by @WillowWisp

• Added dispose() for bottomSheet. by @furkankurt

• Added Pull request template by @unacorbatanegra

• Fix and update documentation: @Farid566, @galaxykhh, @arslee07, @GoStaRoff, @BondarenkoArtur, @denisrudnei, @Charly6596, @nateshmbhat, @hrithikrtiwari, @Undeadlol1, @rws08, @inuyashaaa, @broccolism, @aadarshadhakalg, @ZeroMinJeon