[graphs] update dev dependencies (#1959)

Author: kevmoo

pkgs/graphs/pubspec.yaml

@@ -15,6 +15,6 @@ dev_dependencies:
   test: ^1.21.6
 
   # For examples
-  analyzer: '>=5.2.0 <7.0.0'
+  analyzer: '>=5.2.0 <8.0.0'
   path: ^1.8.0
   pool: ^1.5.0