feat(builder): backport --no-generate option for spa build to 1.x versions (#4127)

* feat(builder): add --no-generate option for SPA mode with v1.x version

* update upath to 1.1.0

* update to puppeteer@1.9.0

bin/nuxt-build

@@ -33,6 +33,7 @@ if (argv.help) {
       --analyze, -a        Launch webpack-bundle-analyzer to optimize your bundles.
       --spa                Launch in SPA mode
       --universal          Launch in Universal mode (default)
+      --no-generate        Don't generate static version for SPA mode (useful for nuxt start)
       --config-file, -c    Path to Nuxt.js config file (default: nuxt.config.js)
       --help, -h           Displays this message
   `)
@@ -65,8 +66,8 @@ const close = () => {
   process.exit(0)
 }
 
-if (options.mode !== 'spa') {
-  // -- Build for SSR app --
+if (options.mode !== 'spa' || argv.generate === false) {
+  // -- Build Only --
   builder
     .build()
     .then(() => debug('Building done'))