MFH: r430489

update thunderbird to 45.6.0

https://www.mozilla.org/en-US/thunderbird/45.6.0/releasenotes/

PR: 215733
Approved by: jbeich (maintainer), rene (mentor, implicit)
Security: 512c0ffd-cd39-4da4-b2dc-81ff4ba8e238

Approved by: ports-secteam (junovitch)