Security update for MozillaThunderbird

This update for MozillaThunderbird fixes the following issues: - Update to 68.8.0 ESR MFSA 2020-18 (bsc#1171186) * CVE-2020-12397 (bmo#1617370) Sender Email Address Spoofing using encoded Unicode characters * CVE-2020-12387 (bmo#1545345) Use-after-free during worker shutdown * CVE-2020-6831 (bmo#1632241) Buffer overflow in SCTP chunk input validation * CVE-2020-12392 (bmo#1614468) Arbitrary local file access with 'Copy as cURL' * CVE-2020-12393 (bmo#1615471) Devtools' 'Copy as cURL' feature did not fully escape website-controlled data, potentially leading to command injection * CVE-2020-12395 (bmo#1595886, bmo#1611482, bmo#1614704, bmo#1624098, bmo#1625749, bmo#1626382, bmo#1628076, bmo#1631508) Memory safety bugs fixed in Thunderbird 68.8.0 This update was imported from the SUSE:SLE-15:Update update project.