Update SDK-specific READMEs

Author: stuartmorgan-g

packages/google_maps_flutter/google_maps_flutter_ios_sdk10/README.md

@@ -1,15 +1,29 @@
-# google\_maps\_flutter\_ios
+# google\_maps\_flutter\_ios\_sdk10
 
-The iOS implementation of [`google_maps_flutter`][1].
+An iOS implementation of [`google_maps_flutter`][1] using
+[Google Maps SDK 10.x][2].
 
 ## Usage
 
-This package is [endorsed][2], which means you can simply use
-`google_maps_flutter` normally. This package will be automatically included in
-your app when you do, so you do not need to add it to your `pubspec.yaml`.
+This package is not the default [endorsed][3] version, so to select this SDK
+version for your implementation you must add a dependency on this package in
+your application's pubspec.yaml. Once you do, it will automatically replace the
+default implementation, then you can use `google_maps_flutter` as normal.
 
-However, if you `import` this package to use any of its APIs directly, you
-should add it to your `pubspec.yaml` as usual.
+### Package Dependencies
+
+If you are authoring a package, please *do not* depend on one of these specific
+implementation packages unless you have a compelling reason to do so. Instead,
+just depend on `google_maps_flutter`, so that application developers can
+select the appropriate SDK version for their minimum iOS version target.
+
+## Minimum iOS Version
+
+Google Maps SDK 10.x requires iOS 16, so if your application does not already
+require iOS 16 you must update your minimum iOS deployment version.
+
+Alternatively, you could use a [different SDK version][4]
+with a lower iOS version requirement.
 
 ## Supported Heatmap Options
 
@@ -22,4 +36,6 @@ should add it to your `pubspec.yaml` as usual.
 | HeatmapGradient.colorMapSize |     ✓     |
 
 [1]: https://pub.dev/packages/google_maps_flutter
-[2]: https://flutter.dev/to/endorsed-federated-plugin
+[2]: https://developers.google.com/maps/documentation/ios-sdk/release-notes
+[3]: https://flutter.dev/to/endorsed-federated-plugin
+[4]: https://pub.dev/packages?q=implements-federated-plugin%3Agoogle_maps_flutter+platform%3Aios

packages/google_maps_flutter/google_maps_flutter_ios_sdk10/example/README.md

@@ -7,7 +7,3 @@ package.
 
 Unless you are making changes to this implementation package, this example is
 very unlikely to be relevant.
-
-## Versions
-
-This example requires iOS 14, so will select a 8.x GoogleMaps SDK version.

packages/google_maps_flutter/google_maps_flutter_ios_sdk9/README.md

@@ -1,15 +1,29 @@
-# google\_maps\_flutter\_ios
+# google\_maps\_flutter\_ios\_sdk10
 
-The iOS implementation of [`google_maps_flutter`][1].
+An iOS implementation of [`google_maps_flutter`][1] using
+[Google Maps SDK 9.x][2].
 
 ## Usage
 
-This package is [endorsed][2], which means you can simply use
-`google_maps_flutter` normally. This package will be automatically included in
-your app when you do, so you do not need to add it to your `pubspec.yaml`.
+This package is not the default [endorsed][3] version, so to select this SDK
+version for your implementation you must add a dependency on this package in
+your application's pubspec.yaml. Once you do, it will automatically replace the
+default implementation, then you can use `google_maps_flutter` as normal.
 
-However, if you `import` this package to use any of its APIs directly, you
-should add it to your `pubspec.yaml` as usual.
+### Package Dependencies
+
+If you are authoring a package, please *do not* depend on one of these specific
+implementation packages unless you have a compelling reason to do so. Instead,
+just depend on `google_maps_flutter`, so that application developers can
+select the appropriate SDK version for their minimum iOS version target.
+
+## Minimum iOS Version
+
+Google Maps SDK 9.x requires iOS 15, so if your application does not already
+require iOS 15 you must update your minimum iOS deployment version.
+
+Alternatively, you could use [`google_maps_flutter_ios`][4] to support
+iOS 14.
 
 ## Supported Heatmap Options
 
@@ -22,4 +36,6 @@ should add it to your `pubspec.yaml` as usual.
 | HeatmapGradient.colorMapSize |     ✓     |
 
 [1]: https://pub.dev/packages/google_maps_flutter
-[2]: https://flutter.dev/to/endorsed-federated-plugin
+[2]: https://developers.google.com/maps/documentation/ios-sdk/release-notes
+[3]: https://flutter.dev/to/endorsed-federated-plugin
+[4]: https://pub.dev/packages/google_maps_flutter_ios

packages/google_maps_flutter/google_maps_flutter_ios_sdk9/example/README.md

@@ -7,7 +7,3 @@ package.
 
 Unless you are making changes to this implementation package, this example is
 very unlikely to be relevant.
-
-## Versions
-
-This example requires iOS 14, so will select a 8.x GoogleMaps SDK version.