[health] Bump dart_apitool (#367)

dart-lang/native#2361 (comment)

bmw-tech/dart_apitool#242

Author: dcharkes

pkgs/firehose/CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 0.12.1-wip
 
 - Make the PR health output less verbose by collapsing warnings by default.
+- Bump dart_apitool to fix errors with equal types being reported as different.
 
 ## 0.12.0
 

pkgs/firehose/lib/src/health/health.dart

@@ -17,7 +17,7 @@ import 'changelog.dart';
 import 'coverage.dart';
 import 'license.dart';
 
-const apiToolHash = '4377249ec08f0fa508298077eae236f24f315e19';
+const apiToolHash = '8654b768219d5707cdade72fdd80cf915e9d46b8';
 
 enum Check {
   license('License Headers', 'license'),