Qt 6.8.0-6.8.3 impacted by heap buffer overflow

- A heap buffer overflow in QTextMarkdownImporter has been discovered. Qt versions 6.8.0-6.8.3 are known to be affected. Patches can be found here:

https://codereview.qt-project.org/c/qt/qtbase/+/635699

- Anonymous access to QtC's Gerrit gitweb has been disabled due to excessive AI crawling.