Helm: fix changelog entry and bump chart version (#11925)

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

This PR fixes the changelog by moving the `bugfix` entry for the cilium
network policies to a separate chart version. The 5.42.2 had already
been released when the said entry was added to it.

**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
- [x] `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](d10549e3ec)
- [ ] If the change is deprecating or removing a configuration option,
update the `deprecated-config.yaml` and `deleted-config.yaml` files
respectively in the `tools/deprecated-config-checker` directory.
[Example
PR](0d4416a4b0)

Signed-off-by: QuantumEnigmaa <thibaud@giantswarm.io>

production/helm/loki/CHANGELOG.md

@@ -13,9 +13,12 @@ Entries should include a reference to the pull request that introduced the chang
 
 [//]: # (<AUTOMATED_UPDATES_LOCATOR> : do not remove this line. This locator is used by the CI pipeline to automatically create a changelog entry for each new Loki release. Add other chart versions and respective changelog entries bellow this line.)
 
-## 5.42.2
+## 5.42.3
 
 - [BUGFIX] Added condition for `egress-discovery` networkPolicies and ciliumNetworkPolicies.
+
+## 5.42.2
+
 - [BUGFIX] Remove trailing tab character in statefulset templates
 
 ## 5.42.1