#!/bin/sh
export LC_ALL=C
echo '2022-12-01T00:00<' >foo
sed -i '/[0-9/][0-9/][0-9/][0-9/]-[0-9/][0-9/]-[0-9/][0-9/]T[0-9/][0-9/]:[0-9/][0-9/]</s/[0-9/][0-9/][0-9/][0-9/]-[0-9/][0-9/]-[0-9/][0-9/]T[0-9/][0-9/]:[0-9/][0-9/]/&:00/g' foo
cat foo