shelf_router_generator: fix deprecated code_builder API (#291)

Author: kevmoo

pkgs/shelf_router_generator/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * Require `analyzer: '>=4.6.0 <6.0.0'`
 * Require `sdk: '>=2.17.0 <3.0.0'`
+* Require `code_builder: ^4.2.0`
 
 ## v1.0.4
 

pkgs/shelf_router_generator/lib/src/shelf_router_generator.dart

@@ -68,7 +68,10 @@ code.Method _buildRouterMethod({
         ..body = code.Block(
           (b) => b
             ..addExpression(
-                code.refer('Router').newInstance([]).assignFinal('router'))
+              code
+                  .declareFinal('router')
+                  .assign(code.refer('Router').newInstance([])),
+            )
             ..statements.addAll(handlers.map((h) => _buildAddHandlerCode(
                   router: code.refer('router'),
                   service: code.refer('service'),

pkgs/shelf_router_generator/pubspec.yaml

@@ -12,7 +12,7 @@ dependencies:
   analyzer: '>=4.6.0 <6.0.0'
   build: ^2.0.0
   build_config: ^1.0.0
-  code_builder: ^4.0.0
+  code_builder: ^4.2.0
   http_methods: ^1.0.0
   shelf: ^1.1.0
   shelf_router: ^1.0.0