misc: Use package-lock.json for Netlify builds

Coses gohugoio#3366

Author: jmooring

.gitignore

@@ -9,5 +9,4 @@
 hugo_stats.json
 node_modules/
 nohup.out
-package-lock.json
 trace.out

netlify.toml

@@ -1,9 +1,10 @@
 [build]
   publish = "public"
-  command = "hugo --gc --minify"
+  command = "npm ci && npm ls && hugo --gc --minify"
 
   [build.environment]
     HUGO_VERSION = "0.155.2"
+    NPM_FLAGS = "--version" # Bypass default 'npm install' to use 'npm ci' in build command
 
 [context.production.environment]
   HUGO_ENV           = "production"