editors/texworks: Update to version 0.6.2.

Texworks is available now as Qt5 only because the upcoming poppler update will not include a Qt4 version.

PR: 200302
Submitted by: tkato432@yahoo.com (original version)
Reviewed by: mat (mentor)
Approved by: tcberner (mentor), hrs (maintainer, timeout)
Differential Revision: https://reviews.freebsd.org/D17177