Bump material to 1.2.1

Author: lcdsmao

build.gradle

@@ -9,7 +9,7 @@ buildscript {
     target_sdk_version = 28
 
     kotlin_version = '1.3.61'
-    material_version = '1.2.0-alpha04'
+    material_version = '1.2.1'
     appcompat_version = '1.2.0'
     core_version = '1.1.0'
   }