Proguard update (#55)

Author: oleksandrsarapulovgl

decoder/proguard-rules.pro

@@ -18,4 +18,6 @@
 
 # If you keep the line number information, uncomment this to
 # hide the original source file name.
-#-renamesourcefileattribute SourceFile
+#-renamesourcefileattribute SourceFile
+-keep public class dgca.verifier.app.decoder.model.*
+-keep public class com.github.fge.jsonschema.** { *; }