Add github action to build releases

Author: scsmithr

Diff for: .github/workflows/build.yaml

@@ -0,0 +1,17 @@
+name: build
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: macos-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Build
+        run: ./ci/build.sh
+      - name: Upload
+        uses: actions/upload-artifact@v2
+        with:
+          name: coder-cli
+          path: ./ci/bin/coder-cli-*