Because build_resolvers >=1.3.8 <1.4.0 depends on build >=1.3.0 <1.4.0 and build_runner 1.11.1 depends on build >=1.5.0 <1.7.0, build_resolvers >=1.3.8 <1.4.0 is incompatible with build_runner 1.11.1. code example

flutter pub run build_runner build