fix: remove too many spaces after colon

docker-compose/prometheus/config/prometheus.yaml

@@ -1,6 +1,6 @@
 ---
 global:
-  scrape_interval:     15s # By default, scrape targets every 15 seconds.
+  scrape_interval: 15s  # By default, scrape targets every 15 seconds.
 
   # Attach these labels to any time series or alerts when communicating with
   # external systems (federation, remote storage, Alertmanager).