compute/v1: make Id a pointer type

Zero is a valid value here. Need to make this a pointer to
differentiate 0 from unset.

Fixes #413

Change-Id: I7b53bdedb33acc76580d4d175b05ba9ee08446eb
Reviewed-on: https://code-review.googlesource.com/c/google-api-go-client/+/54770
Reviewed-by: Chris Broadfoot <cbro@google.com>
diff --git a/google-api-go-generator/gen.go b/google-api-go-generator/gen.go
index b5d1dc1..df94a57 100644
--- a/google-api-go-generator/gen.go
+++ b/google-api-go-generator/gen.go
@@ -902,9 +902,12 @@
 	{api: "cloudmonitoring:v2beta2", schema: "Point", field: "DoubleValue"},
 	{api: "cloudmonitoring:v2beta2", schema: "Point", field: "Int64Value"},
 	{api: "cloudmonitoring:v2beta2", schema: "Point", field: "StringValue"},
+	{api: "compute:alpha", schema: "ExternalVpnGateway", field: "Id"},
 	{api: "compute:alpha", schema: "Scheduling", field: "AutomaticRestart"},
+	{api: "compute:beta", schema: "ExternalVpnGateway", field: "Id"},
 	{api: "compute:beta", schema: "MetadataItems", field: "Value"},
 	{api: "compute:beta", schema: "Scheduling", field: "AutomaticRestart"},
+	{api: "compute:v1", schema: "ExternalVpnGateway", field: "Id"},
 	{api: "compute:v1", schema: "MetadataItems", field: "Value"},
 	{api: "compute:v1", schema: "Scheduling", field: "AutomaticRestart"},
 	{api: "content:v2", schema: "AccountUser", field: "Admin"},