Xournal++ v1.3.6

This is a new minor version of Xournal++ with bug fixes and improvements from the community.

• Fixed several issues with button configuration
• Added mutex locks for lua write functions
• Updated Debian dependency for libxml2
• Added Ubuntu 26.04 (resolute) build target
• Fixed enable/disable copy/cut actions when selecting text in TextEdition
• Fixed data-race related segfault in RenderJob::renderToBuffer()
• Fixed "System default" audio device resolving to null device instead of default
• Fixed compilation warnings
• Fixed several issues with the "Add Pdf Page" dialog
• Updated translations

See https://github.com/xournalpp/xournalpp/blob/v1.3.6/CHANGELOG.md for a more detailled list of changes.