fixup! CI: move

Author: vouillon

.github/workflows/lint.yml

@@ -17,6 +17,9 @@ jobs:
         with:
           ocaml-compiler: "5.2"
           dune-cache: true
+      - name: Pin dune
+        run: |
+          opam pin add -n dune.3.17 https://github.com/ocaml/dune.git
       - uses: ocaml/setup-ocaml/lint-opam@v3
 
   lint-fmt:
@@ -29,6 +32,9 @@ jobs:
         with:
           ocaml-compiler: "5.2"
           dune-cache: true
+      - name: Pin dune
+        run: |
+          opam pin add -n dune.3.17 https://github.com/ocaml/dune.git
       - uses: ocaml/setup-ocaml/lint-fmt@v3
 
   lint-runtime: