Upgrade protobuf plugin version to 0.8.12, android plugin version to 3.5.0 (#6859)

Author: voidzcy

settings.gradle

@@ -1,11 +1,11 @@
 pluginManagement {
     plugins {
-        id "com.android.application" version "3.3.0"
-        id "com.android.library" version "3.3.0"
+        id "com.android.application" version "3.5.0"
+        id "com.android.library" version "3.5.0"
         id "com.github.johnrengelman.shadow" version "2.0.4"
         id "com.github.kt3k.coveralls" version "2.0.1"
         id "com.google.osdetector" version "1.4.0"
-        id "com.google.protobuf" version "0.8.8"
+        id "com.google.protobuf" version "0.8.12"
         id "digital.wup.android-maven-publish" version "3.6.2"
         id "me.champeau.gradle.japicmp" version "0.2.5"
         id "me.champeau.gradle.jmh" version "0.5.0"