Bump ocaml/setup-ocaml from 2 to 3 (#62)

Bumps [ocaml/setup-ocaml](https://github.com/ocaml/setup-ocaml) from 2 to 3.
- [Release notes](https://github.com/ocaml/setup-ocaml/releases)
- [Changelog](https://github.com/ocaml/setup-ocaml/blob/master/CHANGELOG.md)
- [Commits](ocaml/setup-ocaml@v2...v3)

---
updated-dependencies:
- dependency-name: ocaml/setup-ocaml
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/coq-opam-package.yml

@@ -43,7 +43,7 @@ jobs:
 
     steps:
     - name: Set up OCaml
-      uses: ocaml/setup-ocaml@v2
+      uses: ocaml/setup-ocaml@v3
       with:
         ocaml-compiler: ${{ matrix.os.ocaml-compiler }}
         opam-repositories: |-

.github/workflows/coq-windows.yml

@@ -41,7 +41,7 @@ jobs:
       with:
         python-version: 3.x
     - name: Set up OCaml
-      uses: ocaml/setup-ocaml@v2
+      uses: ocaml/setup-ocaml@v3
       with:
         ocaml-compiler: 4.13.1
         opam-repositories: |