[BUG] Gradle 6.8 complains about outputDir property to be deprecated

This generate call done with gradle 6.8 and openapi-generator 5.0.0:

gradlew --warning-mode=all build

causes the following deprecation warning:

Querying the mapped value of task ':xxx:xxx:openApiGenerate' property 'outputDir' before task ':xxx:xxx:openApiGenerate' has completed has been deprecated. This will fail with an error in Gr
adle 7.0. Consult the upgrading guide for further information: https://docs.gradle.org/6.8/userguide/upgrading_version_6.html#querying_a_mapped_output_property_of_a_task_before_the_task_has_completed

This is the generate config for build.gradle

openApiGenerate {
    generatorName = "java"
    library = "resttemplate"
    inputSpec = "${projectDir}/src/main/swagger/Example.yaml"
    outputDir = "${projectDir}/src/generated/"
    apiPackage = "adapter.web.api"
    modelPackage = "adapter.web.model"
    generateApiDocumentation = false
    generateApiTests = false
    configOptions["java8"] = "true"
    configOptions["dateLibrary"] = "java8"
    globalProperties["models"] = ""
}

Currently the ist no way to avoid this message.

Start with the openApiGenerate configuration in build.gradle and reproduce the warning using gradlew --warning-mode=all build with Gradle 6.8. Trace how outputDir is queried before the task completes, then verify that the deprecation warning is resolved and the generation configuration remains compatible with Gradle 7.0.