bugfix: Update docker-compose.yml images and nginx config mount

[vaugenwake]

PR to update the docker-compose.yml template.

Changes:

• Update composer build: to be image:
• Update nginx config mount path to: /docker/nginx/default.conf as /etc/nginx/conf.d/default.conf is a file not a directory
• Update PHP image to be FPM

[willitscale]

Nice spot, just occurred to me I never tested the docker compose