setup-ocaml@v2, sans test

.github/workflows/blank.yml

@@ -0,0 +1,33 @@
+name: CI
+
+# Controls when the action will run. 
+on:
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - macos-latest
+          - ubuntu-latest
+          - windows-latest
+        ocaml-compiler:
+          - 4.12.x
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Use OCaml ${{ matrix.ocaml-compiler }}
+        uses: ocaml/setup-ocaml@v2
+        with:
+          ocaml-compiler: ${{ matrix.ocaml-compiler }}
+
+      - run: opam install . --deps-only
+
+      - run: opam exec -- dune build