Golang json collapse array of an object

Question

In golang how can I collapse an array of an object when returning to json?

I'm not sure how to properly describe this problem but here is what I'm looking for.

{
    "error_code": 422,
    "errors": [
        "email": [
            "email is required"
        ]   
    ]
}

Here's my code so far

type Error struct {
    Email    []string `json:"email"`
}

type Response struct {
    ErrorCode int     `json:"error_code"`
    Errors    []Error `json:"errors"`
}

func handler(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "application/json")
    w.WriteHeader(422)
    
    json.NewEncoder(w).Encode(Response{
        ErrorCode: 422,
        Errors: []Error{
            Error{Email: []string{"email is required"}},
        },
    })
}

and the result is

{
    "error_code": 422,
    "errors": [
        {
            "email": [
                "email is required"
            ]
        }
    ]
}

Notice how errors is an array of object, how can I avoid that and directly have "email" array under "errors"?