build: add flag to distinguish autogenerated libs with a handwritten layer

Google APIs · copybara-github · commit 6bd2087c7599 · 2022-02-24T10:46:09.000-08:00
PiperOrigin-RevId: 430741048
diff --git a/google/spanner/v1/BUILD.bazel b/google/spanner/v1/BUILD.bazel
@@ -233,6 +233,7 @@ nodejs_gapic_library(
     package = "google.spanner.v1",
     service_yaml = "spanner.yaml",
     deps = [],
+    handwritten_layer = True
 )
 
 nodejs_gapic_assembly_pkg(
