major: update default container name

The previous default container name `localstack_main` is not a valid URL, so
we rename the default to `localstack-main`.

See localstack/localstack#9469.

Author: simonrw

docker-compose.yml

@@ -2,7 +2,7 @@ version: "3.8"
 
 services:
   localstack:
-    container_name: "${LOCALSTACK_DOCKER_NAME-localstack_main}"
+    container_name: "${LOCALSTACK_DOCKER_NAME-localstack-main}"
     image: localstack/localstack-pro  # required for Pro
     ports:
       - "127.0.0.1:4566:4566"            # LocalStack Gateway
@@ -17,4 +17,4 @@ services:
       - DOCKER_HOST=unix:///var/run/docker.sock
     volumes:
       - "${LOCALSTACK_VOLUME_DIR:-./volume}:/var/lib/localstack"
-      - "/var/run/docker.sock:/var/run/docker.sock"
+      - "/var/run/docker.sock:/var/run/docker.sock"