Regenerate README file (#317)

Co-authored-by: Alain Schlesser <alain.schlesser@gmail.com>

Author: github-actions[bot]

README.md

@@ -419,7 +419,7 @@ update isn't actually running.
     Downloading update from https://downloads.wordpress.org/release/wordpress-4.5.2-no-content.zip...
     Unpacking the update...
     Cleaning up files...
-    No files found that need cleaning up
+    No old files were removed.
     Success: WordPress updated successfully.
 
     # Update WordPress using zip file.
@@ -433,7 +433,9 @@ update isn't actually running.
     Updating to version 3.1 (en_US)...
     Downloading update from https://wordpress.org/wordpress-3.1.zip...
     Unpacking the update...
-    Warning: Checksums not available for WordPress 3.1/en_US. Please cleanup files manually.
+    Cleaning up files...
+    No old files were removed.
+    Warning: Could not retrieve WordPress core checksums; skipping checksum-based cleanup. Files listed in $_old_files were still cleaned up.
     Success: WordPress updated successfully.