Update to AGP 7.0.0-Alpha12 (#1776)

Fixed robolectric tests.
diff --git a/build.gradle b/build.gradle
index eed0e8b..1c170f6 100644
--- a/build.gradle
+++ b/build.gradle
@@ -16,7 +16,7 @@
   }
   dependencies {
     classpath 'org.ajoberstar:grgit:1.9.3'
-    classpath 'com.android.tools.build:gradle:7.0.0-alpha08'
+    classpath 'com.android.tools.build:gradle:7.0.0-alpha12'
     classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
     classpath "org.jetbrains.kotlin:kotlin-android-extensions:$kotlinVersion"
     classpath 'org.ajoberstar:grgit:1.9.3'