fix: truncate manifest hash

teporary fix until we remove hash :)

Author: pi0

lib/manifest/module.js

@@ -40,7 +40,7 @@ function addManifest (pwa) {
 
   // Stringify manifest & generate hash
   const manifestSource = JSON.stringify(manifest)
-  const manifestFileName = `manifest.${hash(manifestSource)}.json`
+  const manifestFileName = `manifest.${hash(manifestSource).substr(0, 8)}.json`
 
   // Merge final manifest into options.manifest for other modules
   if (!this.options.manifest) {