Android: bump android gradle plugin version

Needed to fix "No toolchains found in the NDK toolchains folder for ABI
with prefix: mips64el-linux-android"

Change-Id: I62d9bae0bf424bb9ba32adce98426245922a841b
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

src/android/templates/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.1'
+        classpath 'com.android.tools.build:gradle:3.2.0'
     }
 }