Prepare 0.38.1 release

Signed-off-by: Stephan Renatus <[email protected]>

CHANGELOG.md

@@ -3,6 +3,19 @@
 All notable changes to this project will be documented in this file. This
 project adheres to [Semantic Versioning](http://semver.org/).
 
+## 0.38.1
+
+This is a bug fix release that addresses one issue when using `opa test` with the
+`--bundle` (`-b`) flag, and a policy that uses the `every` keyword.
+
+There are no other code changes in this release.
+
+### Fixes
+
+- Compiler: don't raise an error with unused declared+generated vars
+  (every) ([#4420](https://github.com/open-policy-agent/opa/issues/4420)),
+  reported by @kristiansvalland
+
 ## 0.38.0
 
 This release contains a number of fixes and enhancements.