Upgrade example project for ios

[ttyniwa]

• Update ios project file to recommended settings by XCode.
  • 
• Regenerate Podfile due to out of date.
  Below error message in AndroidStudio is resolved by this commit.

Exception: Warning: Podfile is out of date
This can cause issues if your application depends on plugins that do not support iOS or macOS.
See https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms for details.
If you have local Podfile edits you would like to keep, see flutter/flutter#45197 for instructions.
To regenerate the Podfile, run:

rm ios/Podfile

btw, I can't resolve below error, and can't run example app.
So this PR may not perfect.
Cloud you tell me how to resolve this one.

ld: library not found for -lflutter_bluetooth_basic
clang: error: linker command failed with exit code 1 (use -v to see invocation)