Update ci.yml

Author: cristianoc

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
         key: ${{matrix.os}}-latest-ocaml-4.06.1
 
     - name: Use OCaml
-      uses: avsm/setup-ocaml@v1.1.10
+      uses: avsm/setup-ocaml@v2
       with:
         ocaml-version: 4.06.1