* In pubspec.yaml the flutter.plugin.{androidPackage,iosPrefix,pluginClass} keys are deprecated. Instead use the flutter.plugin.platforms key introduced in Flutter 1.10.0
There is a typo in your pubspec.yaml. The correct keyword is "platforms", not "platform". So this should fix it:
flutter:
plugin:
platforms:
ios:
pluginClass: FlutterBlePeripheralPlugin
android:
package: dev.steenbakker.flutter_ble_peripheral
pluginClass: FlutterBlePeripheralPlugin