Update GHA scripts

.github/workflows/build.yml

@@ -36,12 +36,12 @@ jobs:
           git config --global core.eol lf
 
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
-      - name: Use Node.js 18.x
-        uses: actions/setup-node@v3
+      - name: Use latest Node.js
+        uses: actions/setup-node@v4
         with:
-          node-version: 18.x
+          node-version: latest
 
       - name: Use OCaml ${{ matrix.ocaml-compiler }}
         uses: ocaml/setup-ocaml@v2
@@ -59,8 +59,8 @@ jobs:
           opam-local-packages: $${ matrix.opam-local-packages }}
           opam-depext-flags: --with-test
           opam-repositories: |
-            opam-repository-mingw: https://github.com/ocaml-opam/opam-repository-mingw.git#sunset
-            default: https://github.com/ocaml/opam-repository.git
+            opam-repository-mingw: git+https://github.com/dra27/opam-repository.git#windows-initial
+            default: git+https://github.com/ocaml/opam-repository.git
 
       - run: |
           opam pin add alcotest-async.dev ./ -n