Add section for 2.7.5 patch release (#8920)

**What this PR does / why we need it**:
Add a section for the 2.7.5 release.

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

Signed-off-by: Michel Hollands <michel.hollands@grafana.com>

CHANGELOG.md

@@ -30,6 +30,14 @@
 
 ### Dependencies
 
+## 2.7.5 (2023-03-28)
+
+#### Loki
+
+##### Fixes
+
+* [7924](https://github.com/grafana/loki/pull/7924) **jeschkies**: Flush buffered logger on exit
+
 ## 2.7.4 (2023-02-24)
 
 #### Loki