Security update for MozillaThunderbird

This update for MozillaThunderbird fixes the following issues: Update to version 78.13 (MFSA 2021-35, bsc#1188891) - CVE-2021-29986: Race condition when resolving DNS names could have led to memory corruption - CVE-2021-29988: Memory corruption as a result of incorrect style treatment - CVE-2021-29984: Incorrect instruction reordering during JIT optimization - CVE-2021-29980: Uninitialized memory in a canvas object could have led to memory corruption - CVE-2021-29985: Use-after-free media channels - CVE-2021-29989: Memory safety bugs fixed in Thunderbird 78.13