Fix OpenAPIEdgeGatewayEdgeCluster struct (vmware#688)

Signed-off-by: abarreiro <abarreiro@vmware.com>

.changes/v2.25.0/688-bug-fixes.md

@@ -0,0 +1,2 @@
+* Fixed an error that occurred when updating an Edge Gateway configuration, with an Edge cluster configuration section
+  (`OpenAPIEdgeGatewayEdgeClusterConfig`). If this section was added, the update operation failed in VCD 10.6+ [GH-688]

govcd/nsxt_edgegateway_test.go

@@ -62,6 +62,15 @@ func (vcd *TestVCD) Test_NsxtEdgeCreate(check *C) {
 	openApiEndpoint := types.OpenApiPathVersion1_0_0 + types.OpenApiEndpointEdgeGateways + createdEdge.EdgeGateway.ID
 	AddToCleanupListOpenApi(createdEdge.EdgeGateway.Name, check.TestName(), openApiEndpoint)
 
+	edgeCluster, err := nsxtVdc.GetNsxtEdgeClusterByName(vcd.config.VCD.Nsxt.NsxtEdgeCluster)
+	check.Assert(err, IsNil)
+	check.Assert(edgeCluster, NotNil)
+
+	createdEdge.EdgeGateway.EdgeClusterConfig = &types.OpenAPIEdgeGatewayEdgeClusterConfig{
+		PrimaryEdgeCluster: types.OpenAPIEdgeGatewayEdgeCluster{
+			BackingID: edgeCluster.NsxtEdgeCluster.ID,
+		},
+	}
 	createdEdge.EdgeGateway.Name = "renamed-edge"
 	updatedEdge, err := createdEdge.Update(createdEdge.EdgeGateway)
 	check.Assert(err, IsNil)

types/v56/nsxt_types.go

@@ -134,8 +134,8 @@ type OpenAPIEdgeGatewayBacking struct {
 
 // OpenAPIEdgeGatewayEdgeCluster allows users to specify edge cluster reference
 type OpenAPIEdgeGatewayEdgeCluster struct {
-	EdgeClusterRef OpenApiReference `json:"edgeClusterRef"`
-	BackingID      string           `json:"backingId"`
+	EdgeClusterRef *OpenApiReference `json:"edgeClusterRef"`
+	BackingID      string            `json:"backingId"`
 }
 
 type OpenAPIEdgeGatewayEdgeClusterConfig struct {