With PrismaORM 6.6 "DATABASE_URL" Cannot Be Found

error: Environment variable not found: DATABASE_URL.
  -->  schema.prisma:9
   | 
 8 |   provider = "mysql"
 9 |   url      = env("DATABASE_URL")
   | 

generator client {
  provider = "prisma-client"
  output   = "../generated/prisma"
  moduleFormat = "esm"
}

datasource db {
  provider = "mysql"
  url      = env("DATABASE_URL")
}