chore: upgrade example to Docker Compose v2 (#39372)

Upgrade the README to use Docker Compose v2, which is faster and shipped by default with Docker Desktop since April.

## Documentation / Examples

- [x] Make sure the linting passes by running `pnpm lint`
- [x] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)

examples/with-docker-compose/README.md

@@ -41,10 +41,10 @@ First, run the development server:
 docker network create my_network
 
 # Build dev using new BuildKit engine
-COMPOSE_DOCKER_CLI_BUILD=1 DOCKER_BUILDKIT=1 docker-compose -f docker-compose.dev.yml build --parallel
+docker compose -f docker-compose.dev.yml build
 
 # Up dev
-docker-compose -f docker-compose.dev.yml up
+docker compose -f docker-compose.dev.yml up
 ```
 
 Open [http://localhost:3000](http://localhost:3000) with your browser to see the result.
@@ -63,10 +63,10 @@ First, run the production server (Final image approximately 110 MB).
 docker network create my_network
 
 # Build prod using new BuildKit engine
-COMPOSE_DOCKER_CLI_BUILD=1 DOCKER_BUILDKIT=1 docker-compose -f docker-compose.prod.yml build --parallel
+docker compose -f docker-compose.prod.yml build
 
 # Up prod in detached mode
-docker-compose -f docker-compose.prod.yml up -d
+docker compose -f docker-compose.prod.yml up -d
 ```
 
 Alternatively, run the production server without without multistage builds (Final image approximately 1 GB).
@@ -77,10 +77,10 @@ Alternatively, run the production server without without multistage builds (Fina
 docker network create my_network
 
 # Build prod without multistage using new BuildKit engine
-COMPOSE_DOCKER_CLI_BUILD=1 DOCKER_BUILDKIT=1 docker-compose -f docker-compose.prod-without-multistage.yml build --parallel
+docker compose -f docker-compose.prod-without-multistage.yml build
 
 # Up prod without multistage in detached mode
-docker-compose -f docker-compose.prod-without-multistage.yml up -d
+docker compose -f docker-compose.prod-without-multistage.yml up -d
 ```
 
 Open [http://localhost:3000](http://localhost:3000).