Add missing release notes for 2.8.2 (#9389)

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

Part of v2.8.2 release

---------

Co-authored-by: J Stickler <julie.stickler@grafana.com>

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

@@ -22,8 +22,12 @@ As always, please read the [upgrade guide]({{<relref "../upgrading/#270">}}) bef
 
 ## Bug fixes
 
-### 2.8.1 (2023-04-21)
+### 2.8.2 (2023-05-03)
+
+* Update Go to 1.20.4 to address security vulnerabilities in the previous Go version.
+* *Promtail*: Add new `decompression` configuration to customize the decompressor behavior.
 
+### 2.8.1 (2023-04-21)
 
 * Fix bug that was dropping index if period is a zero value.
 * Fix redis client to prevent it from incorrectly choosing cluster mode with local address.