Bump update_engine version to 8 am: 39a6a4cb3b

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1995530

Change-Id: Idbd201e92a367ed7973a9c7f32e632e242fc540f
diff --git a/update_engine.conf b/update_engine.conf
index b6ca3c4..2d3a655 100644
--- a/update_engine.conf
+++ b/update_engine.conf
@@ -1,2 +1,2 @@
 PAYLOAD_MAJOR_VERSION=2
-PAYLOAD_MINOR_VERSION=7
+PAYLOAD_MINOR_VERSION=8