Skip update-responses xml files for versions which don't have incrementals

With the 14.5.1 update, the file linux-x86_64/.htaccess contains this:

RewriteEngine On
RewriteRule ^13.5.16/ no-update.xml [last]
RewriteRule ^13.5.13/ 13.5.13-14.5.1+13.5.16-linux-x86_64.xml [last]
RewriteRule ^13.5.14/ 13.5.14-14.5.1+13.5.16-linux-x86_64.xml [last]
RewriteRule ^13.5.15/ 13.5.15-14.5.1+13.5.16-linux-x86_64.xml [last]
RewriteRule ^14.0.7/ 14.0.7-14.5.1+13.5.16-linux-x86_64.xml [last]
RewriteRule ^14.0.8/ 14.0.8-14.5.1+13.5.16-linux-x86_64.xml [last]
RewriteRule ^14.0.9/ 14.0.9-14.5.1+13.5.16-linux-x86_64.xml [last]
RewriteRule ^14.5/ 14.5-14.5.1+13.5.16-linux-x86_64.xml [last]
RewriteRule ^[^/]+/ 14.5.1+13.5.16-linux-x86_64.xml [last]

However the files 13.5.*.xml don't contain any incrementals, since the legacy version is only for macOS and Windows. We could skip generating those files.