Support the latest build_test package (#232)

diff --git a/pubspec.yaml b/pubspec.yaml
index 1802ede..37d7db0 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -14,7 +14,7 @@
   test: ^1.6.0
 
   build_runner: ^1.0.0
-  build_test: ^0.10.0
+  build_test: ^1.2.0
   build_web_compilers: '>=1.2.0 <3.0.0'
 
 dependency_overrides: