Fix strict language checks (flutter#6622)

Author: kevmoo

analysis_options.yaml

@@ -22,7 +22,7 @@
 # repository.
 
 analyzer:
-  strong-mode:
+  language:
     strict-casts: true
     strict-raw-types: true
   errors:

packages/google_sign_in/google_sign_in_web/lib/src/generated/gapiauth2.dart

@@ -12,7 +12,7 @@
 
 // https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/gapi.auth2
 
-// ignore_for_file: public_member_api_docs, unused_element, non_constant_identifier_names, sort_constructors_first, always_specify_types
+// ignore_for_file: public_member_api_docs, unused_element, non_constant_identifier_names, sort_constructors_first, always_specify_types, strict_raw_type
 
 @JS()
 library gapiauth2;

packages/in_app_purchase/in_app_purchase_storekit/test/fakes/fake_storekit_platform.dart

@@ -176,7 +176,7 @@ class FakeStoreKitPlatform {
         if (call.arguments['applicationUsername'] == 'userWithDiscount') {
           if (call.arguments['paymentDiscount'] != null) {
             final Map<dynamic, dynamic> discountArgument =
-                call.arguments['paymentDiscount'];
+                call.arguments['paymentDiscount'] as Map<dynamic, dynamic>;
             discountReceived = discountArgument.cast<String, dynamic>();
           } else {
             discountReceived = <String, dynamic>{};