Add CI test for building CLI.

.github/workflows/test.yml

@@ -47,3 +47,15 @@ jobs:
         token: ${{ secrets.CODECOV_TOKEN }}
         file: ./coverage.txt
         fail_ci_if_error: true
+
+  build-cli:
+    name: Build CLI
+    runs-on: ubuntu-latest
+    needs: [lint]
+    steps:
+    - uses: actions/checkout@main
+    - uses: actions/setup-go@main
+      with:
+        go-version: '1.13'
+    - name: Run go build
+      run: go build ./cli/battlesnake