allow build version 2.4.x from build_runner (#3499)

Author: jakemac53

build_runner/CHANGELOG.md

@@ -1,4 +1,6 @@
-## 2.4.2-wip
+## 2.4.2
+
+- Support package:build version 2.4.x.
 
 ## 2.4.1
 

build_runner/pubspec.yaml

@@ -1,5 +1,5 @@
 name: build_runner
-version: 2.4.2-wip
+version: 2.4.2
 description: A build system for Dart code generation and modular compilation.
 repository: https://github.com/dart-lang/build/tree/master/build_runner
 
@@ -15,7 +15,7 @@ dependencies:
   analyzer: '>=4.4.0 <6.0.0'
   args: ^2.0.0
   async: ^2.5.0
-  build: ">=2.1.0 <2.4.0"
+  build: ">=2.1.0 <2.5.0"
   build_config: ">=1.1.0 <1.2.0"
   build_daemon: ^4.0.0
   build_resolvers: ^2.0.0