Support latest pkg:analyzer, release v6.7.1 (#1333)

Author: kevmoo

json_serializable/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 6.7.1
+
+- Support the latest `package:analyzer`.
+
 ## 6.7.0
 
 - Support `Record` types.

json_serializable/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_serializable
-version: 6.7.0
+version: 6.7.1
 description: >-
   Automatically generate code for converting to and from JSON by annotating
   Dart classes.
@@ -13,7 +13,7 @@ topics:
  - codegen
 
 dependencies:
-  analyzer: ^5.12.0
+  analyzer: '>=5.12.0 <7.0.0'
   async: ^2.8.0
   build: ^2.0.0
   build_config: '>=0.4.4 <2.0.0'