Laravel Lower Version 5.6v Project Dockerize Problem

composer.json

{
    "name": "laravel/laravel",
    "description": "The Laravel Framework.",
    "keywords": ["framework", "laravel"],
    "license": "MIT",
    "type": "project",
    "require": {
        "php": "^7.1.3",
        "fideloper/proxy": "^4.0",
        "guzzlehttp/guzzle": "^6.3",
        "laravel/framework": "5.6.*",
        "laravel/tinker": "^1.0"
    },
    "require-dev": {
        "filp/whoops": "^2.0",
        "fzaninotto/faker": "^1.4",
        "mockery/mockery": "^1.0",
        "nunomaduro/collision": "^2.0",
        "phpunit/phpunit": "^7.0",
        "xethron/migrations-generator": "^2.0"
    },
    "autoload": {
        "classmap": [
            "database/seeds",
            "database/factories"
        ],
        "psr-4": {
            "App\\": "app/"
        }
    },
    "autoload-dev": {
        "psr-4": {
            "Tests\\": "tests/"
        }
    },
    "extra": {
        "laravel": {
            "dont-discover": [
            ]
        }
    },
    "scripts": {
        "post-root-package-install": [
            "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
        ],
        "post-create-project-cmd": [
            "@php artisan key:generate"
        ],
        "post-autoload-dump": [
            "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump",
            "@php artisan package:discover"
        ]
    },
    "config": {
        "preferred-install": "dist",
        "sort-packages": true,
        "optimize-autoloader": true,
        "allow-plugins": {
            "kylekatarnls/update-helper": true
        }
    },
    "minimum-stability": "dev",
    "prefer-stable": true
}

docker-compose.yml

version: '3.3'

services:
  db:
    image: mysql:8
    command: mysqld --default-authentication-plugin=mysql_native_password --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci
    environment:
      - "MYSQL_ROOT_PASSWORD=${DB_PASSWORD}"
      - "MYSQL_DATABASE=${DB_DATABASE}"
    volumes:
      - ${BACKUP_PATH}/mysql:/var/lib/mysql
    ports:
      - ${DB_PORT_EXPOSE}:3306
    networks:
      - sizram

  php:
    build:
      context: ./docker/site
      args:
        - PHP_VERSION=${PHP_VERSION:-8.0.2}
    volumes:
      - ./:/var/www/site:cached
    networks:
      - sizram

  nginx:
    image: nginx:alpine
    ports:
      - "${APP_PORT:-8299}:80"
    volumes:
      - ./docker/nginx/default.conf:/etc/nginx/conf.d/default.conf:cached
      - ./docker/nginx/nginx.conf:/etc/nginx/nginx.conf:cached
      - ./:/var/www/site:cached
    networks:
      - sizram

networks:
  sizram:

env

APP_NAME=Laravel
APP_ENV=local
APP_KEY=base64:5CqAbdffipNkPf167+3T8GdrVIDgLKEMzbvjw5R5DfE=
APP_DEBUG=true
APP_URL=http://localhost

LOG_CHANNEL=stack
LOG_DEPRECATIONS_CHANNEL=null
LOG_LEVEL=debug

###Docker Related Configuration
APP_PORT=8799
BACKUP_PATH=../backup/sizram
DB_PORT_EXPOSE=33059

DB_CONNECTION=mysql
DB_HOST=db
DB_PORT=3306
DB_DATABASE=sizram_school
DB_USERNAME=root
DB_PASSWORD=root

BROADCAST_DRIVER=log
CACHE_DRIVER=file
FILESYSTEM_DISK=local
QUEUE_CONNECTION=sync
SESSION_DRIVER=file
SESSION_LIFETIME=120

MEMCACHED_HOST=memcached

REDIS_HOST=redis
REDIS_PASSWORD=null
REDIS_PORT=6379

MAIL_MAILER=smtp
MAIL_HOST=mailhog
MAIL_PORT=1025
MAIL_USERNAME=null
MAIL_PASSWORD=null
MAIL_ENCRYPTION=null
MAIL_FROM_ADDRESS="hello@example.com"
MAIL_FROM_NAME="${APP_NAME}"

AWS_ACCESS_KEY_ID=
AWS_SECRET_ACCESS_KEY=
AWS_DEFAULT_REGION=us-east-1
AWS_BUCKET=
AWS_USE_PATH_STYLE_ENDPOINT=false

PUSHER_APP_ID=
PUSHER_APP_KEY=
PUSHER_APP_SECRET=
PUSHER_APP_CLUSTER=mt1

MIX_PUSHER_APP_KEY="${PUSHER_APP_KEY}"
MIX_PUSHER_APP_CLUSTER="${PUSHER_APP_CLUSTER}"

SCOUT_DRIVER=meilisearch
MEILISEARCH_HOST=http://meilisearch:7700