Update Prometheus and Grafana versions

Remove `privileged:true` since its a huge security issue. No longer needed.
Change placeholder for MDH image to an actual tag number.

docker/docker-compose.yml

@@ -4,7 +4,7 @@ services:
 
   mangadex-at-home:
     container_name: mangadex-at-home
-    image: "registry.gitlab.com/mangadex-pub/mangadex_at_home:<version>"
+    image: "registry.gitlab.com/mangadex-pub/mangadex_at_home:2"
     ports:
       - 443:443
     volumes:
@@ -12,7 +12,6 @@ services:
       - ./data/cache/:/mangahome/data/
     environment:
       JAVA_TOOL_OPTIONS: "-Xms1G -Xmx1G -XX:+UseShenandoahGC -Xss512K"
-    privileged: true
     command: [
         "bash",
         "-c",
@@ -31,7 +30,7 @@ services:
 
   prometheus:
     container_name: prometheus
-    image: prom/prometheus:v2.24.1
+    image: prom/prometheus:v2.34.0
     user: "root"
     group_add:
       - 0
@@ -50,7 +49,7 @@ services:
 
   grafana:
     container_name: grafana
-    image: grafana/grafana:7.4.0
+    image: grafana/grafana:8.4.3
     user: "root"
     group_add:
       - 0