[FIX] website_blog: correct RSS feed

Order blogs by post_date
write_date is changed each time a new visitor reach the page (number of visit)

Fixes tw:legalsylvain/status/951559451399671808
Closes #22198

addons/website_blog/controllers/main.py

@@ -177,7 +177,9 @@ class WebsiteBlog(http.Controller):
         v = {}
         v['blog'] = blog
         v['base_url'] = request.env['ir.config_parameter'].get_param('web.base.url')
-        v['posts'] = request.env['blog.post'].search([('blog_id','=', blog.id)], limit=min(int(limit), 50))
+        v['posts'] = request.env['blog.post'].search([('blog_id','=', blog.id)],
+            limit=min(int(limit), 50),
+            order="post_date DESC")
         v['html2plaintext'] = html2plaintext
         r = request.render("website_blog.blog_feed", v, headers=[('Content-Type', 'application/atom+xml')])
         return r

addons/website_blog/views/website_blog_templates.xml

@@ -552,14 +552,14 @@
     <title t-esc="blog.name"/>
     <link t-att-href="'%s/blog/%s' % (base_url ,blog.id)"/>
     <id t-esc="'%s/blog/%s' % (base_url, blog.id)"/>
-    <updated t-esc="(posts[0] if posts else blog).write_date.replace(' ', 'T') + 'Z'"/>
+    <updated t-esc="(posts[0] if posts else blog).post_date.replace(' ', 'T') + 'Z'"/>
     <entry t-foreach="posts" t-as="post">
         <title t-esc="post.name"/>
         <link t-att-href="'%s%s' % (base_url, post.website_url)"/>
         <id t-esc="'%s%s' % (base_url, post.website_url)"/>
         <author><name t-esc="post.sudo().author_id.name"/></author>
         <summary t-esc="html2plaintext(post.teaser)"/>
-        <updated t-esc="post.write_date.replace(' ', 'T') + 'Z'"/>
+        <updated t-esc="post.post_date.replace(' ', 'T') + 'Z'"/>
     </entry>
 </feed>
 </template>