Bug 1567807. Use a newer gradle for wrench. r=nalexander

This gets the wrench android builds working again after
07168db23c565e4506690612a7be50738844ddb2.

Differential Revision: https://phabricator.services.mozilla.com/D38882

--HG--
extra : moz-landing-system : lando

taskcluster/scripts/misc/wrench-android-build.sh

@@ -18,7 +18,7 @@ buildscript {
         maven{ url uri('file:${GECKO_PATH}/android-gradle-dependencies/jcenter') }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.4'
+        classpath 'com.android.tools.build:gradle:3.2.1'
     }
 }
 allprojects {