syncthing: bump to 1.29.6

syncthing: bump to 1.29.6

- chore(lib): expose model methods to obtain progress
- feat(gui): explanation to options enabled or disabled per folder type
- fix(gui): validate device ID in canonical form
- fix(config): remove discontinued primary STUN server
- fix(stun): better error handling
- chore(config): remove discontinued secondary STUN servers
- chore(fs): speed up case normalization
- build(deps): update dependencies
- feat(fs, config): add support for custom filesystem type construction
- build: replace underscore in Debian version
- chore(model): add metric for total number of conflicts
- fix(config): properly apply defaults when reading folder configuration
- fix(config): zero filesystemtype is "basic"
- build: push artifacts to Azure
- chore(config): resolve primary STUN servers via SRV record
- chore(fs): changes to allow Filesystem to be implemented externally
- fix(strings): differentiate setup(n) and set(v) up
- fix(gui): mark unseen disconnected devices as inactive
- fix(syncthing): use separate lock file instead of locking the
  certificate
- feat(api, gui): allow authentication bypass for metrics
- chore: add missing copyright in new files from infra branch
- fix(osutil): give threads same I/O priority on Linux
- chore(syncthing): remove support for TLS 1.2 sync connections
- chore(gui): update dependency copyrights, add script for periodic
  maintenance
- chore(api): log X-Forwarded-For
- feat(config): add option for audit file
- chore(gui): use go list --deps for dependency list
- fix(strelaysrv): make the session limiter session-dependent

Changelog: https://github.com/syncthing/syncthing/compare/v1.29.5...v1.29.6
Signed-off-by: George Sapkin <redacted>