Makefile: use docker compose not docker-compose (segmentio#1309)

As part of the Docker binary this will be updated more often and has
better support and newer features than the separate "docker-compose"
binary.

Makefile

@@ -4,4 +4,4 @@ test:
  go test -race -cover ./...
 
 docker:
- docker-compose up -d
+ docker compose up -d