chore: Missed version updates. (#10676)

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

```
LOKI_NEW_VERSION=2.9.1 ./tools/release_update_tags.sh
```

This script was introduced as the part of release docs PR.
https://github.com/grafana/loki/pull/10646

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

**Special notes for your reviewer**:

**Checklist**
- [x] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [x] Documentation added

---------

Signed-off-by: Kaviraj <kavirajkanagaraj@gmail.com>
Co-authored-by: Christian Haudum <christian.haudum@gmail.com>

examples/getting-started/docker-compose.yaml

@@ -6,7 +6,7 @@ networks:
 
 services:
   read:
-    image: grafana/loki:2.9.0
+    image: grafana/loki:2.9.1
     command: "-config.file=/etc/loki/config.yaml -target=read"
     ports:
       - 3101:3100
@@ -27,7 +27,7 @@ services:
           - loki
 
   write:
-    image: grafana/loki:2.9.0
+    image: grafana/loki:2.9.1
     command: "-config.file=/etc/loki/config.yaml -target=write"
     ports:
       - 3102:3100
@@ -46,7 +46,7 @@ services:
       <<: *loki-dns
 
   promtail:
-    image: grafana/promtail:2.9.0
+    image: grafana/promtail:2.9.1
     volumes:
       - ./promtail-local-config.yaml:/etc/promtail/config.yaml:ro
       - /var/run/docker.sock:/var/run/docker.sock