Update Wasm_of_ocaml action (#11184)

The attempts to update the workflow as Wasm_of_ocaml has been merged
upstream in ocsigen/js_of_ocaml#1724 and the
wasm-dune branch is gone.

Signed-off-by: Marek Kubica <marek@tarides.com>

Author: Leonidas-from-XIV

.github/workflows/workflow.yml

@@ -254,8 +254,7 @@ jobs:
       - name: Checkout Wasm_of_ocaml
         uses: actions/checkout@v4
         with:
-          repository: ocaml-wasm/wasm_of_ocaml
-          ref: wasm-dune
+          repository: ocsigen/js_of_ocaml
           path: wasm_of_ocaml
 
       - name: Install Wasm_of_ocaml