Update docs 2.8.2 (#9379)

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

Update docs and changelog with Loki 2.8.2 changes.

**Which issue(s) this PR fixes**:
Fixes #<issue number>

**Special notes for your reviewer**:

**Checklist**
- [ ] 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`

examples/getting-started/docker-compose.yaml

@@ -6,7 +6,7 @@ networks:
 
 services:
   read:
-    image: grafana/loki:2.8.0
+    image: grafana/loki:2.8.2
     command: "-config.file=/etc/loki/config.yaml -target=read"
     ports:
       - 3101:3100
@@ -27,7 +27,7 @@ services:
           - loki
 
   write:
-    image: grafana/loki:2.8.0
+    image: grafana/loki:2.8.2
     command: "-config.file=/etc/loki/config.yaml -target=write"
     ports:
       - 3102:3100
@@ -46,7 +46,7 @@ services:
       <<: *loki-dns
 
   promtail:
-    image: grafana/promtail:2.8.0
+    image: grafana/promtail:2.8.2
     volumes:
       - ./promtail-local-config.yaml:/etc/promtail/config.yaml:ro
       - /var/run/docker.sock:/var/run/docker.sock