1.8.6

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- Job is now optional for thunar_io_scan_directory
- Expand scroll window of file operation progress dialog (Bug #14946)
- Fix compiler error -Wcast-function-type (GCC 8)
- Bump glib minimal required version
- Fix g_type_class_add_private is deprecated
- Small code cleanup
- Fix pathbar to on middle click open folders in new tabs (Bug #15302)
- Translation updates: Danish