feat: Add hexo-generator-feed to generate Atom feed (#1999)

This commit adds the `hexo-generator-feed` plugin to generate an Atom feed for the blog.

The following changes were made:
- Added `hexo-generator-feed` to `blog/package.json`.
- Configured the feed plugin in `blog/_config.yml` to generate an Atom feed at `atom.xml`.
- Updated the theme configuration in `blog/themes/freewill/_config.yml` to point to the new feed.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: johan456789

blog/_config.yml

@@ -82,3 +82,9 @@ deploy:
 
 include:
   - .nojekyll
+
+# Feed
+feed:
+  type: atom
+  path: atom.xml
+  limit: 20

blog/package-lock.json

@@ -10,6 +10,7 @@
     "hexo-deployer-git": "^4.0.0",
     "hexo-generator-archive": "^2.0.0",
     "hexo-generator-category": "^2.0.0",
+    "hexo-generator-feed": "^3.0.0",
     "hexo-generator-index": "^4.0.0",
     "hexo-generator-tag": "^2.0.0",
     "hexo-renderer-ejs": "^2.0.0",

blog/package.json

@@ -57,7 +57,7 @@ widgets:
 - recent_posts
 - links
 
-rss: true
+rss: atom.xml
 fancybox: true
 favicon: favicon.png
 google_analytics: