Update Gradle plugin to work with latest Android Studio 3.3 Canary 8

Just like the other commit, this will be reverted once the feature is working.
I simply don't want to deal with what changes in my installation of Android
Studio 3.1.4 Stable which breaks the layout preview rendering.

app/build.gradle

@@ -14,7 +14,7 @@ def getGitSha = { ->
 
 android {
     compileSdkVersion 27
-    buildToolsVersion '27.0.3'
+//    buildToolsVersion '27.0.3'
     defaultConfig {
         applicationId "com.keylesspalace.tusky"
         minSdkVersion 19

build.gradle

@@ -7,7 +7,8 @@ buildscript {
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.3.0-alpha07'
+//        classpath 'com.android.tools.build:gradle:3.1.4'
+        classpath 'com.android.tools.build:gradle:3.3.0-alpha08'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }