Ensure usage of stan-0.2.1.0 to fix haskell#541

Fixed by: kowainik/stan#586
Released in stan-0.2.1.0

Author: 0rphee

cabal.project

@@ -8,7 +8,7 @@ packages:
          ./hls-test-utils
 
 
-index-state: 2025-05-12T13:26:29Z
+index-state: 2025-06-07T14:57:40Z
 
 tests: True
 test-show-details: direct

haskell-language-server.cabal

@@ -801,7 +801,7 @@ library hls-stan-plugin
     , lsp-types
     , text
     , unordered-containers
-    , stan >= 0.1.2.0
+    , stan >= 0.2.1.0
     , trial
     , directory