Update leap second table to 28 Dec 2025 based on IERS Bulletin C 69#103

yunjunz merged 1 commit intoinsarlab:maininsarlab/PySolid:mainfrom

AndreHauschild:updateLeapsecondValidityIntervalAndreHauschild/PySolid:updateLeapsecondValidityIntervalCopy head branch name to clipboard