Reduce the external files required for gem installation

assets/feed.xml

@@ -1,5 +1,6 @@
 ---
 layout: compress
+permalink: /feed.xml
 # Atom Feed, reference: https://validator.w3.org/feed/docs/atom.html
 ---
 

assets/js/pwa/app.js

@@ -1,5 +1,6 @@
 ---
 layout: compress
+permalink: '/app.js'
 ---
 
 /* Registering Service Worker */

assets/js/pwa/sw.js

@@ -1,5 +1,6 @@
 ---
 layout: compress
+permalink: '/sw.js'
 # PWA service worker
 ---
 

assets/robots.txt

@@ -1,5 +1,5 @@
 ---
-permalink: robots.txt
+permalink: /robots.txt
 # The robots rules
 ---
 

jekyll-theme-chirpy.gemspec

@@ -11,7 +11,7 @@ Gem::Specification.new do |spec|
   spec.license       = "MIT"
 
   spec.files         = `git ls-files -z`.split("\x0").select { |f|
-    f.match(%r!^((assets\/(css|img|js\/[a-z])|_(includes|layouts|sass|config|data|tabs|plugins))|README|LICENSE|index|feed|app|sw|404|robots)!i)
+    f.match(%r!^((assets\/(css|img|js\/[a-z])|_(includes|layouts|sass|config|data|tabs|plugins))|README|LICENSE|index)!i)
   }
 
   spec.metadata = {