Merge pull request #768 from ChristianLempa/renovate/grafana-promtail-3.4.x

chore(deps): update grafana/promtail docker tag to v3.4.2

docker-compose/promtail/compose.yaml

@@ -1,7 +1,7 @@
 ---
 services:
   promtail:
-    image: grafana/promtail:3.4.1
+    image: grafana/promtail:3.4.2
     command: "-config.file=/mnt/config/config.yaml"
     volumes:
       - ./config/config.yaml:/mnt/config/config.yaml:ro