Fix the go vet warnings

[haoxins]

What type of PR is this?

• bug
• feature
• enhancement

$ go vet ./...

# github.com/vesoft-inc/nebula-go/v3
./result_set_test.go:158:31: github.com/vesoft-inc/nebula-go/v3/nebula.Date struct literal uses unkeyed fields
./result_set_test.go:165:31: github.com/vesoft-inc/nebula-go/v3/nebula.Time struct literal uses unkeyed fields
./result_set_test.go:181:14: github.com/vesoft-inc/nebula-go/v3/nebula.Time struct literal uses unkeyed fields
./result_set_test.go:190:13: github.com/vesoft-inc/nebula-go/v3/nebula.Time struct literal uses unkeyed fields
./result_set_test.go:199:13: github.com/vesoft-inc/nebula-go/v3/nebula.Time struct literal uses unkeyed fields
./result_set_test.go:208:13: github.com/vesoft-inc/nebula-go/v3/nebula.Time struct literal uses unkeyed fields
./result_set_test.go:217:13: github.com/vesoft-inc/nebula-go/v3/nebula.Time struct literal uses unkeyed fields
./result_set_test.go:224:32: github.com/vesoft-inc/nebula-go/v3/nebula.DateTime struct literal uses unkeyed fields
./result_set_test.go:239:14: github.com/vesoft-inc/nebula-go/v3/nebula.DateTime struct literal uses unkeyed fields
./result_set_test.go:249:13: github.com/vesoft-inc/nebula-go/v3/nebula.DateTime struct literal uses unkeyed fields
./result_set_test.go:259:13: github.com/vesoft-inc/nebula-go/v3/nebula.DateTime struct literal uses unkeyed fields
./result_set_test.go:269:13: github.com/vesoft-inc/nebula-go/v3/nebula.DateTime struct literal uses unkeyed fields
./result_set_test.go:305:48: github.com/vesoft-inc/nebula-go/v3/nebula.DateTime struct literal uses unkeyed fields
./result_set_test.go:311:13: github.com/vesoft-inc/nebula-go/v3/nebula.Vertex struct literal uses unkeyed fields
./result_set_test.go:351:48: github.com/vesoft-inc/nebula-go/v3/nebula.DateTime struct literal uses unkeyed fields
./result_set_test.go:423:32: github.com/vesoft-inc/nebula-go/v3/nebula.Duration struct literal uses unkeyed fields
./result_set_test.go:545:18: github.com/vesoft-inc/nebula-go/v3/nebula/graph.ExecutionResponse struct literal uses unkeyed fields
./result_set_test.go:565:14: github.com/vesoft-inc/nebula-go/v3/nebula/graph.PlanDescription struct literal uses unkeyed fields
./result_set_test.go:567:4: *github.com/vesoft-inc/nebula-go/v3/nebula/graph.PlanNodeDescription struct literal uses unkeyed fields
./result_set_test.go:575:4: *github.com/vesoft-inc/nebula-go/v3/nebula/graph.PlanNodeDescription struct literal uses unkeyed fields
./result_set_test.go:589:11: github.com/vesoft-inc/nebula-go/v3/nebula/graph.ExecutionResponse struct literal uses unkeyed fields
./result_set_test.go:668:11: github.com/vesoft-inc/nebula-go/v3/nebula/graph.ExecutionResponse struct literal uses unkeyed fields
./result_set_test.go:715:11: github.com/vesoft-inc/nebula-go/v3/nebula/graph.ExecutionResponse struct literal uses unkeyed fields
./result_set_test.go:907:10: github.com/vesoft-inc/nebula-go/v3/nebula.Row struct literal uses unkeyed fields

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[haoxins]

cc @Nicole00 @wey-gu