Update custom_apns.py

Issue when building on ubuntu 20.10.  changed line 24 to reflect correct path.

Change-Id: I6ba997b7e8c73f068516f1069e22137e31ece2dc
diff --git a/tools/custom_apns.py b/tools/custom_apns.py
index b58ece1..9ba0907 100644
--- a/tools/custom_apns.py
+++ b/tools/custom_apns.py
@@ -21,7 +21,7 @@
 def main(argv):
     reload(sys)
     sys.setdefaultencoding('utf8')
-    original_file = 'vendor/lineage/prebuilt/common/etc/apns-conf.xml'
+    original_file = 'vendor/bliss/prebuilt/common/etc/apns-conf.xml'
 
     if len(argv) == 3:
         output_file_path = argv[1]