sysutils/gdisk: Update to 1.0.3

• Complete the conversion to options helpers

• Add LICENSE_FILE

• Reset maintainer after a timeout of 3 years + 2 months

Changes: https://sourceforge.net/p/gptfdisk/code/ci/master/tree/NEWS
PR: 223855
Submitted by: John Hein <z7dr6ut7gs@snkmail.com> (based on)
Approved by: wg (maintainer timeout, 2 months)