Where should I set aspectVersion to use aspejct.gradle plugin?

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1

aspectj.gradle plugin mandate to set aspectJVersion before applying it. Hence, I write my code as below. However, only buildscript {} and other plugins {} are allowed to show before plugins {}. So, where should I set apsectJversion in my build? PS. I am using gradle 5.0

project.ext {
aspectjVersion ‘1.8.9’
}

plugins {
id ‘aspectj.gradle’ version ‘0.1.6’
}