Security update for MozillaThunderbird

This update for MozillaThunderbird fixes the following security issues: - CVE-2019-11703: Fixed a heap-based buffer overflow in icalmemorystrdupanddequote() (bsc#1137595). - CVE-2019-11704: Fixed a heap-based buffer overflow in parser_get_next_char() (bsc#1137595). - CVE-2019-11705: Fixed a stack-based buffer overflow in icalrecur_add_bydayrules() (bsc#1137595). - CVE-2019-11706: Fixed a type confusion in icaltimezone_get_vtimezone_properties() (bsc#1137595). This update was imported from the SUSE:SLE-15:Update update project.