fixed environment assign error

docker-compose example on https://hub.docker.com/r/pihole/pihole is wrong, and I was stupid by not checking it before copypasting...

docker-compose.yml

@@ -6,8 +6,8 @@ services:
     container_name: ${PH_CONTAINER_NAME}
     restart: unless-stopped
     environment:
-      - TZ: "${PH_TIMEZONE}"
-      - WEBPASSWORD: "${PH_WEBPASSWORD}"
+      - TZ="${PH_TIMEZONE}"
+      - WEBPASSWORD="${PH_WEBPASSWORD}"
     labels:
       - traefik.enable=true
       - traefik.docker.network=traefik-proxy