Fix "depext unmet availability conditions" GH actions CI (rescript-lang#454)

Co-authored-by: Iwan <[email protected]>

Author: IwanKaramazow

syntax/.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
         key: macos-latest-ocaml-4.06.1
 
     - name: Use OCaml
-      uses: avsm/setup-ocaml@v1.1.10
+      uses: ocaml/setup-ocaml@v1
       with:
         ocaml-version: 4.06.1