add a github action to download something

.github/workflows/download.yml

@@ -0,0 +1,35 @@
+name: http download
+
+on: [push, pull_request]
+
+jobs:
+  tests:
+    name: Tests
+
+    strategy:
+      matrix:
+        ocaml-version: ["4.14.1"]
+        operating-system: [ubuntu-latest]
+
+    runs-on: ${{ matrix.operating-system }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Use OCaml ${{ matrix.ocaml-version }}
+        uses: ocaml/setup-ocaml@v2
+        with:
+          ocaml-compiler: ${{ matrix.ocaml-version }}
+
+      - name: Install dependencies
+        run: opam install --deps-only -t .
+
+      - name: Build
+        run: opam exec -- dune build
+
+      - name: Test
+        run: opam exec -- dune runtest
+
+      - name: Download
+        run: opam exec -- dune exec -- app/hurl.exe https://google.com > /dev/null