CocoaPods not installed. Skipping pod install

When building for ios, sometimes this error appears:

Warning: CocoaPods not installed. Skipping pod install.
  CocoaPods is used to retrieve the iOS and macOS platform side's plugin code that responds to your plugin usage on the Dart side.
  Without CocoaPods, plugins will not work on iOS or macOS.
  For more info, see https://flutter.dev/platform-plugins
To install see https://guides.cocoapods.org/using/getting-started.html#installation for instructions.

CocoaPods not installed or not in valid state.
Error launching application on iPhone 13.

More info here.

What seems to work#

Open a separate shell, then run:

sudo gem install cocoapods

Then close VSCode entirely, reopen it, and build again.