Add proguard to extension-template

hi guys im trying to add proguard to extension-template
i made changes in build.xml
but i got this

ProGuard:
[taskdef] Could not load definitions from resource proguard/ant/task.properties. It could not be found.

BUILD FAILED
C:\Users\fa\extension-template\build.xml:95: The following error occurred while executing this line:
C:\Users\fa\extension-template\build.xml:110: The following error occurred while executing this line:
C:\Users\fa\extension-template\build.xml:188: Problem: failed to create task or type proguard
Cause: The name is undefined.
Action: Check the spelling.
Action: Check that any custom tasks/types have been declared.
Action: Check that any / declarations have taken place

idk if im doing it wrong or what i placed proguard in libs and added the lines that in github how to do it then ?

guys anyone ?

@Flag_Dz I have pushed a change that reconciles the changes @Diego made to App Inventor sources with the template repo.