Docker compose: Update loki and promtail version tags to 2.7.1 (#8230)

**What this PR does / why we need it**:

Updated loki and promtail version tags to the latest.

**Which issue(s) this PR fixes**:


**Special notes for your reviewer**:

**Checklist**
- [x] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [ ] Documentation added
- [ ] Tests updated
- [ ] `CHANGELOG.md` updated
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/upgrading/_index.md`

production/docker-compose.yaml

@@ -5,7 +5,7 @@ networks:
 
 services:
   loki:
-    image: grafana/loki:2.6.1
+    image: grafana/loki:2.7.1
     ports:
       - "3100:3100"
     command: -config.file=/etc/loki/local-config.yaml
@@ -13,7 +13,7 @@ services:
       - loki
 
   promtail:
-    image: grafana/promtail:2.6.1
+    image: grafana/promtail:2.7.1
     volumes:
       - /var/log:/var/log
     command: -config.file=/etc/promtail/config.yml