Add preupload hook to remind people to use AOSP

Add a preupload hook for Telecom to remind people to use AOSP for
Telecom changes.

Test: manual
Change-Id: If2a2cedf95dd14b2fa61ca54762937e586e59aff
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
new file mode 100644
index 0000000..9874044
--- /dev/null
+++ b/PREUPLOAD.cfg
@@ -0,0 +1,2 @@
+[Hook Scripts]
+aosp_hook = ${REPO_ROOT}/packages/services/Telecomm/scripts/aosp_tag_preupload.py ${PREUPLOAD_COMMIT}