[release-2.8.x] add release notes for 2.8.6 (#10935)

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

**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
- [ ] If the change is worth mentioning in the release notes, add
`add-to-release-notes` label
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/setup/upgrade/_index.md`
- [ ] For Helm chart changes bump the Helm chart version in
`production/helm/loki/Chart.yaml` and update
`production/helm/loki/CHANGELOG.md` and
`production/helm/loki/README.md`. [Example
PR](d10549e)

docs/sources/release-notes/v2-8.md

@@ -22,6 +22,10 @@ As always, please read the [upgrade guide]({{<relref "../upgrading/#270">}}) bef
 
 ## Bug fixes
 
+### 2.8.6 (2023-10-17)
+
+* Upgrade go to v1.20.10, golang.org/x/net to v0.17.0 and grpc-go to v1.56.3 to patch CVE-2023-39325 / CVE-2023-44487
+
 ### 2.8.5 (2023-09-14)
 
 * Update Docker base images to mitigate security vulnerability CVE-2022-48174
@@ -46,4 +50,4 @@ As always, please read the [upgrade guide]({{<relref "../upgrading/#270">}}) bef
 * Update alpine image to 3.16.5 to address security vulnerabilities in the previous version.
 * *Promtail*: Fix journald support in amd64 binary build.
 
-For a full list of all changes and fixes, look at the [CHANGELOG](https://github.com/grafana/loki/blob/release-2.8.x/CHANGELOG.md).
+For a full list of all changes and fixes, look at the [CHANGELOG](https://github.com/grafana/loki/blob/release-2.8.x/CHANGELOG.md).