Para formatar a hora, usamos o método Format() que formata um objeto time.Time.
func (t Time) Format(layout string) string
package main
import (
"fmt"
"time"
)
func main() {
current_time := time.Now()
fmt.Printf("%d-%02d-%02dT%02d:%02d:%02d-00:00\n",
current_time.Year(), current_time.Month(), current_time.Day(),
current_time.Hour(), current_time.Minute(), current_time.Second())
fmt.Println(current_time.Format("2006-01-02 15:04:05"))
fmt.Println(current_time.Format("2006-January-02"))
fmt.Println(current_time.Format("2006-01-02 3:4:5 pm"))
}