Compile with Android Q SDK

We upgrade compileSdkVersion to Q, but keep targetSdkVersion as 28.
The reason is because targeting Q will no longer allow us to execute
native binaries in an app's private data, which Magisk Manager relies
a lot for performing stock boot image patches in non rooted environment.
For more information regarding this issue, check this link:
https://redd.it/b2inbu

Some workarounds has been discovered (https://github.com/termux/proot),
however for the time being there is no point to introduce these huge
hacks just for targeting Q, which we don't benefit anything.

build.gradle

@@ -43,8 +43,8 @@ subprojects {
         if (getPlugins().hasPlugin('com.android.library') ||
             getPlugins().hasPlugin('com.android.application')) {
             android {
-                compileSdkVersion 28
-                buildToolsVersion "28.0.3"
+                compileSdkVersion 'android-Q'
+                buildToolsVersion '29.0.0-rc2'
 
                 defaultConfig {
                     if (minSdkVersion == null)