Update error message for new policy.

A new presubmit hook enforces that required information is present in
any CL that adds new dependencies to allowed_deps.txt.

Test: m
Bug: 195303213
Change-Id: I1fb932a52f64f9cbf0d12ead75ffd3d9c2a5e942
diff --git a/apex/apex_singleton.go b/apex/apex_singleton.go
index 0ed94af..9178431 100644
--- a/apex/apex_singleton.go
+++ b/apex/apex_singleton.go
@@ -59,8 +59,15 @@
 				echo "******************************";
 				echo "Detected changes to allowed dependencies in updatable modules.";
 				echo "To fix and update packages/modules/common/build/allowed_deps.txt, please run:";
-				echo "$$ (croot && packages/modules/common/build/update-apex-allowed-deps.sh)";
-				echo "Members of mainline-modularization@google.com will review the changes.";
+				echo -e "$$ (croot && packages/modules/common/build/update-apex-allowed-deps.sh)\n";
+				echo "When submitting the generated CL, you must include the following information";
+				echo "in the commit message if you are adding a new dependency:";
+				echo "Apex-Size-Increase:";
+				echo "Previous-Platform-Support:";
+				echo "Aosp-First:";
+				echo "Test-Info:";
+				echo "You do not need OWNERS approval to submit the change, but mainline-modularization@";
+				echo "will periodically review additions and may require changes.";
 				echo -e "******************************\n";
 				exit 1;
 			fi;