Detect Android SDK 28/28.0.3 (#26942)

* Detect Android SDK 28/28.0.3

* revert minimumAndroidSdkVersion const change

packages/flutter_tools/lib/src/base/user_messages.dart

diff --git a/packages/flutter_tools/lib/src/base/user_messages.dart b/packages/flutter_tools/lib/src/base/user_messages.dart
index 2248d11..813247c 100644
--- a/packages/flutter_tools/lib/src/base/user_messages.dart
+++ b/packages/flutter_tools/lib/src/base/user_messages.dart
@@ -76,7 +76,7 @@
   String get androidLicensesSome => 'Some Android licenses not accepted.  To resolve this, run: flutter doctor --android-licenses';
   String get androidLicensesNone => 'Android licenses not accepted.  To resolve this, run: flutter doctor --android-licenses';
   String get androidLicensesUnknown => 'Android license status unknown.';
-  String androidSdkOutdated(String managerPath) =>
+  String androidSdkManagerOutdated(String managerPath) =>
       'A newer version of the Android SDK is required. To update, run:\n'
       '$managerPath --update\n';
   String androidLicensesTimeout(String managerPath) => 'Intentionally killing $managerPath';
@@ -85,6 +85,11 @@
       'Android sdkmanager tool not found ($sdkManagerPath).\n'
       'Try re-installing or updating your Android SDK,\n'
       'visit https://flutter.io/setup/#android-setup for detailed instructions.';
+  String androidSdkBuildToolsOutdated(String managerPath, int sdkMinVersion, String buildToolsMinVersion) =>
+      'Flutter requires Android SDK $sdkMinVersion and the Android BuildTools $buildToolsMinVersion\n'
+      'To update using sdkmanager, run:\n'
+      '  $managerPath "platforms;android-$sdkMinVersion" "build-tools;$buildToolsMinVersion"\n'
+      'or visit https://flutter.io/setup/#android-setup for detailed instructions.';
 
   // Messages used in AndroidStudioValidator
   String androidStudioVersion(String version) => 'version $version';