[google_maps_flutter] Add SDK 11 package for iOS #193449

Version 11 of the Google Maps SDK for iOS was released in August, so with the per-SDK package structure there will need to be a new copy created that uses SDK 11. This will be the first SwiftPM-only version, as there's no CocoaPods release of v11.

Surprisingly, this release didn't drop any iOS versions as the releases have done in past years; it still supports iOS 16+. That means that in theory, it could be added as a range to the _sdk10 package, but that would be pretty confusing, so I would recommend just making a new _sdk11 package anyways (even though I'm not aware of any reason someone would want to use 10 instead of 11 at this point). The release notes don't call out any changes, so presumably all the source can continue to be shared.