Fix blog post link (#12287)

Missed this one in
#12282

Author: stsewd

readthedocs/notifications/messages.py

@@ -227,7 +227,7 @@ def get_rendered_body(self):
                 This build has failed because the current deploy key on the repository was created with write permission.
                 For protection against abuse we've restricted use of these deploy keys.
                 A read-only deploy key will need to be set up <b>before July 31, 2025</b> to continue building this project.
-                Read more about this in our <a href="https://about.readthedocs.com/blog/2025/05/ssh-keys-with-write-access/">blog post</a>.
+                Read more about this in our <a href="https://about.readthedocs.com/blog/2025/07/ssh-keys-with-write-access/">blog post</a>.
                 """
             ).strip(),
         ),