www/chromium: Update to version 83.0.4103.97

Submitted by: Matthias Wolf <freebsd@rheinwolf.de> via [1]
Approved by: chromium@ (rene)
MFH: 2020Q2
Security: https://chromereleases.googleblog.com/2020/06/stable-channel-update-for-desktop.html

[1] https://github.com/gliaskos/freebsd-chromium