Bump patch version to 0.38.9 (#1121)

Author: mhauru

HISTORY.md

@@ -18,6 +18,10 @@ We intend to replace `LogDensityFunction` with `FastLDF` in a release in the nea
 
 For more information about `FastLDF`, please see https://github.com/TuringLang/DynamicPPL.jl/pull/1113 as well as the `src/fasteval.jl` file, which contains extensive comments.
 
+## 0.38.9
+
+Remove warning when using Enzyme as the AD backend.
+
 ## 0.38.8
 
 Added a new exported struct, `DynamicPPL.ParamsWithStats`.