Replace use of deprecated IncrementalTaskInputs

[dpatriarche]

The gradle-frontend-plugin uses deprecated Gradle APIs that will be removed in Gradle 8.0. When building a project with Gradle 7.5.1 the following warnings are output:

$ ./gradlew clean build --warning-mode all
> Configure project :my-project
IncrementalTaskInputs has been deprecated. This is scheduled to be removed in Gradle 8.0. On method 'CssMinifyTask.minifyCss' use 'org.gradle.work.InputChanges' instead. Consult the upgrading guide for further information: https://docs.gradle.org/7.5.1/userguide/upgrading_version_7.html#incremental_task_inputs_deprecation
IncrementalTaskInputs has been deprecated. This is scheduled to be removed in Gradle 8.0. On method 'JsMinifyTask.compileJs' use 'org.gradle.work.InputChanges' instead. Consult the upgrading guide for further information: https://docs.gradle.org/7.5.1/userguide/upgrading_version_7.html#incremental_task_inputs_deprecation
IncrementalTaskInputs has been deprecated. This is scheduled to be removed in Gradle 8.0. On method 'JsMergeTask.mergeJavascript' use 'org.gradle.work.InputChanges' instead. Consult the upgrading guide for further information: https://docs.gradle.org/7.5.1/userguide/upgrading_version_7.html#incremental_task_inputs_deprecation