JavaCompile variant is obsolete

[codeanticode]

The JavaCompile variant used in the hack to enable building sketches using ECJ in Gradle now triggers the following warning:

> Task :wear:compileDebugJavaWithJavac
WARNING: API 'variant.getJavaCompile()' is obsolete and has been replaced with 'variant.getJavaCompileProvider()'.
It will be removed in version 5.0 of the Android Gradle plugin.
For more information, see https://d.android.com/r/tools/task-configuration-avoidance.
To determine what is calling variant.getJavaCompile(), use -Pandroid.debug.obsoleteApi=true on the command line to display more information.

So it seems it needs to be replaced by JavaCompileProvider, as long as it allows running the ECJ hack.

[codeanticode]

Fixed by Updating build template files in 2018d85 following these changes.