Update TEST_MAPPING

Test: None
Change-Id: I06066be2397df082dd9ec02b6e611d536358d909
diff --git a/TEST_MAPPING b/TEST_MAPPING
new file mode 100644
index 0000000..54c111f
--- /dev/null
+++ b/TEST_MAPPING
@@ -0,0 +1,8 @@
+// Generated by update_crate_tests.py for tests that depend on this crate.
+{
+  "presubmit": [
+    {
+      "name": "libgrpc_bindgen_test"
+    }
+  ]
+}