RichHelpFormatter does not replace %(prog)s in text

[hamdanal]

$ cat t.py
import argparse

from rich_argparse import RichHelpFormatter

parser = argparse.ArgumentParser(
    "awesome_program",
    description="This is the %(prog)s program.",
    formatter_class=RichHelpFormatter,
)
parser.add_argument("--version", action="version", version="%(prog)s 1.0.0")
parser.parse_args()

$ python t.py --version
%(prog)s 1.0.0

$ python t.py --help
usage: awesome_program [-h] [--version]

This is the %(prog)s program.

OPTIONS
  -h, --help  show this help message and exit
  --version   show program's version number and exit

Expected behaviour: replace %(prog)s by awesome_program in the printed text