Upgrade build.gradle and eliminate warnings

build.gradle

@@ -1,7 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.3.41'
+    ext.kotlin_version = '1.3.72'
     repositories {
         google()
         jcenter()
@@ -10,11 +10,11 @@ buildscript {
         }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.6.3'
+        classpath 'com.android.tools.build:gradle:3.6.4'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath 'io.realm:realm-gradle-plugin:5.15.2'
         classpath 'com.google.gms:google-services:4.3.3'
-        classpath 'io.fabric.tools:gradle:1.28.1'
+        classpath 'io.fabric.tools:gradle:1.31.2'
     }
 }