-- Remove podfile and podfile.lock...By using command (re ios/podfile && rm ios/podfile.lock)
-- Then Update each and every package in your flutter project by using comand (flutter pub upgrade)
-- Then Use (flutter pub upgrade --major-versions) this command to upgrade to major version of all packages
-- Flutter clean
-- Flutter Run (Try to run from IDE in IOS Simulator if the app gets built try to open IOS folder in XCODE)
-- From There again try to run the app.