rev the min. recommended flutter plugin version (#11501)

diff --git a/packages/flutter_tools/lib/src/doctor.dart b/packages/flutter_tools/lib/src/doctor.dart
index eee4ecd..3447e8d 100644
--- a/packages/flutter_tools/lib/src/doctor.dart
+++ b/packages/flutter_tools/lib/src/doctor.dart
@@ -255,7 +255,7 @@
   };
 
   static final Version kMinIdeaVersion = new Version(2017, 1, 0);
-  static final Version kMinFlutterPluginVersion = new Version(14, 0, 0);
+  static final Version kMinFlutterPluginVersion = new Version(16, 0, 0);
 
   static Iterable<DoctorValidator> get installedValidators {
     if (platform.isLinux || platform.isWindows)