Lock ocaml/setup-ocaml to last working version. (#12201)

.github/workflows/main.yml

@@ -53,7 +53,8 @@ jobs:
         run: neko -version 2>&1
 
       - name: Setup ocaml
-        uses: ocaml/setup-ocaml@v3
+      # Lock to 3.2.19 to work around an issue with 32-bit libraries getting installed
+        uses: ocaml/setup-ocaml@3d85bf33a66e089149cd1e9c75da7b9cb6d9d3a7
         with:
           ocaml-compiler: ${{ env.OCAML_VERSION }}
           opam-local-packages: |

extra/github-actions/install-ocaml-windows.yml

@@ -1,5 +1,6 @@
 - name: Setup ocaml
-  uses: ocaml/setup-ocaml@v3
+# Lock to 3.2.19 to work around an issue with 32-bit libraries getting installed
+  uses: ocaml/setup-ocaml@3d85bf33a66e089149cd1e9c75da7b9cb6d9d3a7
   with:
     ocaml-compiler: ${{ env.OCAML_VERSION }}
     opam-local-packages: |