update proguard

Author: robin4002

build.gradle

@@ -8,7 +8,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath 'net.sf.proguard:proguard-gradle:4.10'
+        classpath 'net.sf.proguard:proguard-gradle:5.2.1'
     }
 }