Set Hugo env to production (#196)

diff --git a/landing-pages/package.json b/landing-pages/package.json
index 56c480d..c40b6ac 100644
--- a/landing-pages/package.json
+++ b/landing-pages/package.json
@@ -8,7 +8,7 @@
   "license": "MIT",
   "scripts": {
     "build": "npm run build:webpack && npm run build:hugo",
-    "build:hugo": "hugo -d ../dist -s site -v",
+    "build:hugo": "cross-env HUGO_ENV=production hugo -d ../dist -s site -v",
     "build:hugo:preview": "npm run build:hugo -- -D -F",
     "build:preview": "npm run build:webpack && npm run build:hugo:preview",
     "build:webpack": "cross-env NODE_ENV=production webpack --config webpack.prod.js",