generator: drop build bits. Not used. (#419)

Author: kevmoo

web_generator/pubspec.yaml

@@ -10,8 +10,6 @@ environment:
 dependencies:
   analyzer: ^7.4.0
   args: ^2.4.0
-  build_runner: ^2.4.6
-  build_web_compilers: ^4.0.8
   code_builder: ^4.10.0
   dart_flutter_team_lints: ^3.0.0
   dart_style: ^3.0.0
@@ -22,5 +20,6 @@ dependencies:
   pub_semver: ^2.1.5
   test: ^1.24.4
   yaml: ^3.1.3
+
 dev_dependencies:
   web: ^1.1.1