Update netlify.toml (#409)

Author: Arhell

netlify.toml

@@ -1,18 +1,18 @@
 [context.production.environment]
   HUGO_VERSION = "0.119.0"
+  NODE_VERSION = "18"
 
 [context.deploy-preview.environment]
   HUGO_VERSION = "0.119.0"
+  NODE_VERSION = "18"
 
 [context.branch-deploy.environment]
   HUGO_VERSION = "0.119.0"
-
-[context.deploy-preview]
-command = "cd themes/docsy && git submodule update -f --init && cd ../.. && hugo --gc --minify"
+  NODE_VERSION = "18"
 
 [build]
   publish = "public"
-  command = "cd themes/docsy && git submodule update -f --init && cd ../.. && hugo --gc --minify"
+  command = "cd themes/docsy && git submodule update -f --init && npm install && cd ../.. && hugo --gc --minify"
 
 [[plugins]]
 package = "@algolia/netlify-plugin-crawler"