Log Message:
thunderbird: Update to 68.8.0

Changelog:
Fixes
Account Manager: text fields were too small in some cases
Account Manager: Authentication method did not update when selecting an SMTP server
Links with embedded credentials did not open on Windows
Messages were sometimes sent with a badly formed address when filled from the \ 
address book
Accessibility: Screen readers were reporting too many activities from the status bar
MailExtensions: Setting IMAP messages as read with browser.messages.updated \ 
failed to persist
Various security fixes

Security fixes:
#CVE-2020-12397: Sender Email Address Spoofing using encoded Unicode characters
#CVE-2020-12387: Use-after-free during worker shutdown
#CVE-2020-6831: Buffer overflow in SCTP chunk input validation
#CVE-2020-12392: Arbitrary local file access with 'Copy as cURL'
#CVE-2020-12393: Devtools' 'Copy as cURL' feature did not fully escape \ 
website-controlled data, potentially leading to command injection
#CVE-2020-12395: Memory safety bugs fixed in Thunderbird 68.8.0