Merge pull request #1256 from austinhuang0131/renovate/com.android.tools.build-gradle-4.x

Update dependency com.android.tools.build:gradle to v4.2.1

build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.2.0'
+        classpath 'com.android.tools.build:gradle:4.2.1'
         def nav_version = "2.3.5"
         classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version"
     }