Android Studio plugin development: GradleBuildFile no longer found in com.android.tools.idea.gradle.parser.GradleBuildFile

Hi,

which jar do you need to import for the below import statements?  Please help, my plugin project 

IntelliJ IDEA 2020.2.2 (Community Edition)
Build #IC-202.7319.50, built on September 14, 2020
Runtime version: 11.0.8+10-b944.31 x86_64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
macOS 10.15.5
GC: ParNew, ConcurrentMarkSweep
Memory: 1979M
Cores: 16
Non-Bundled Plugins: org.jetbrains.kotlin

import com.android.tools.idea.gradle.dsl.parser.BuildFileKey;
import com.android.tools.idea.gradle.BuildFileKey;
import com.android.tools.idea.gradle.parser.GradleBuildFile;