Update build.yml

Author: yforster

.github/workflows/build.yml

@@ -19,7 +19,7 @@ jobs:
       - name: Install OCaml
         uses: avsm/setup-ocaml@v1
         with:
-          ocaml-version: 4.07.1
+          ocaml-version: 4.11.0
 
       - name: Checkout code
         uses: actions/checkout@v2