Using a dynamic year isn't fully supported as it makes the auto-
generation depend on the date. Also we do not need to update the
year in the copyright notices for any files in ANGLE.

Bug: angleproject:2621
Change-Id: I123864e77bffe8e04e5b299f0c58853c89287372
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2552980
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>