Could not resolve all artifacts for configuration ':cryptography_flutter:classpath'.

[sgorbyo]

Enabling cryptography_flutter I'm not able to compile due to the following gradle error.

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ':cryptography_flutter'.
> Could not resolve all artifacts for configuration ':cryptography_flutter:classpath'.
   > Could not find com.android.extensions.build:gradle:4.1.1.
     Searched in the following locations:
       - https://dl.google.com/dl/android/maven2/com/android/extensions/build/gradle/4.1.1/gradle-4.1.1.pom
       - https://repo.maven.apache.org/maven2/com/android/extensions/build/gradle/4.1.1/gradle-4.1.1.pom
     Required by:
         project :cryptography_flutter
> Failed to notify project evaluation listener.
   > Could not get unknown property 'android' for project ':cryptography_flutter' of type org.gradle.api.Project.
   > Could not get unknown property 'android' for project ':cryptography_flutter' of type org.gradle.api.Project.