RFC - attempt at a github build action

.github/workflows/main.yml

@@ -0,0 +1,47 @@
+# This is a basic workflow to help you get started with Actions
+
+name: CI
+
+# Controls when the action will run. 
+on:
+  # Triggers the workflow on push or pull request events but only for the master branch
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+# A workflow run is made up of one or more jobs that can run sequentially or in parallel
+jobs:
+  # This workflow contains a single job called "build"
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+        ocaml-version:
+          - 4.11.2
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Use OCaml ${{ matrix.ocaml-version }}
+        uses: avsm/setup-ocaml@v1
+        with:
+          ocaml-version: ${{ matrix.ocaml-version }}
+
+      - run: opam install ./makecloud.opam.locked --deps-only --unlock-base -y
+
+      - run: eval $(opam env) && dune build
+
+      - name: Upload CLI
+        uses: actions/upload-artifact@v2
+        with:
+          name: makecloud-cli
+          path: _build/default/cli/main.exe