1. Change templates to `IPHONEOS_DEPLOYMENT_TARGET`, `MinimumOSVersion`, and Podfile `platform :ios` to 12.0. 2. Add migrator for Podfile part to migrate `platform :ios, '11.0'` -> `platform :ios, '12.0'` 3. Compile with `-miphoneos-version-min=12.0` 4. Run the migrator on all example apps and integration tests. See also https://github.com/flutter/flutter/pull/62902 and https://github.com/flutter/flutter/pull/85174 and https://github.com/flutter/flutter/pull/101963 Fixes https://github.com/flutter/flutter/issues/136060
* Add ios to integration test and comments * Add licenses * Fix integration test for ios * Delete pngs * Undo changes to integration test * Undo error * Add ios task * Fix task for landing
