问源驱动程序:未知驱动程序postgres (忘记导入？)即使正在导入lib/pq

EN

source driver: unknown driver postgres (forgotten import?)

package main

import (
    "database/sql"
    "log"
    "os"

    "github.com/golang-migrate/migrate/v4"
    _ "github.com/golang-migrate/migrate/v4/database/postgres"
    _ "github.com/golang-migrate/migrate/v4/source/file"
    _ "github.com/lib/pq"

    "github.com/joho/godotenv"
)

func init() {
    if err := godotenv.Load(".env"); err != nil {
        log.Println("no .env file found")
    }
}

func main() {
     db_url := os.Getenv("POSTGRES_URL");
     mig_url := os.Getenv("MIGRATION_URL")
    MustMigrateUp(db_url, mig_url)

     _, err := sql.Open("postgres", db_url)
    if err != nil {
        log.Fatal(err)
    }
}

func MustMigrateUp(db_url, mig_url string) {
    m, err := migrate.New(
        db_url,
        mig_url,
    )
    println(os.Getenv("POSTGRES_URL"))
    if err != nil {
        log.Fatalln(err)
    }

    if err := m.Up(); err != nil {
        log.Fatalln(err)
    }
}