Remove opam-repositories from CI as it is no longer needed

Author: filipeom

.github/workflows/build.yml

@@ -20,7 +20,6 @@ jobs:
         uses: ocaml/setup-ocaml@v3
         with:
           ocaml-compiler: "5.3"
-          opam-repositories: "default: https://opam.ocaml.org"
 
       - name: Install dependencies
         run: opam install -y . --deps-only --with-dev-setup
@@ -51,7 +50,6 @@ jobs:
         uses: ocaml/setup-ocaml@v3
         with:
           ocaml-compiler: ${{ matrix.ocaml-compiler }}
-          opam-repositories: "default: https://opam.ocaml.org"
           dune-cache: true
 
       - name: Install dependencies
@@ -85,7 +83,6 @@ jobs:
         uses: ocaml/setup-ocaml@v3
         with:
           ocaml-compiler: "5.3"
-          opam-repositories: "default: https://opam.ocaml.org"
           dune-cache: true
 
       - name: Install ${{ matrix.solver }}

.github/workflows/deploy.yml

@@ -28,7 +28,6 @@ jobs:
         uses: ocaml/setup-ocaml@v3
         with:
           ocaml-compiler: "5.3"
-          opam-repositories: "default: https://opam.ocaml.org"
           dune-cache: true
 
       - name: Setup Pages

.github/workflows/publish.yml

@@ -22,7 +22,6 @@ jobs:
         uses: ocaml/setup-ocaml@v3
         with:
           ocaml-compiler: "5.3"
-          opam-repositories: "default: https://opam.ocaml.org"
 
       - name: Install dependencies
         run: opam install opam-publish