Use newer spine extension v2.5.0

this fixes build errors: m_Objects is a private member of dmObjectPool

game.project

@@ -1,7 +1,7 @@
 [project]
 title = Defold-examples
 version = 0.1
-dependencies#0 = https://github.com/defold/extension-spine/archive/refs/tags/2.3.1.zip
+dependencies#0 = https://github.com/defold/extension-spine/archive/refs/tags/2.5.0.zip
 
 [bootstrap]
 main_collection = /examples/main.collectionc