Fix repo upload fail if no symbolic link to python3

generate_annotation_enums.py was added to repo hook but it specific
pthon instrad of python3, on system without symbolic link to python3 from python, repo upload would failed with a file not found error.

Test: Manual test
Bug: 287123042
Change-Id: I61167c5e97bcabb0b0c1b86971f19ce483ff198f
diff --git a/automotive/vehicle/tools/generate_annotation_enums.py b/automotive/vehicle/tools/generate_annotation_enums.py
index 06e9745..cfae607 100755
--- a/automotive/vehicle/tools/generate_annotation_enums.py
+++ b/automotive/vehicle/tools/generate_annotation_enums.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 # Copyright (C) 2022 The Android Open Source Project
 #