* Update and rename check_valid_ip_address.py to is_ip_v4_address_valid.py
New test cases that the algorithm must detect:
* [ ] an octet much bigger than 255
* [ ] an octet is negative
* [ ] number of octets is less than 4
* [ ] number of octets is greater than 4
* [ ] an octet is a letter
* updating DIRECTORY.md
* Add two more tests to is_ip_v4_address_valid.py
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: John Law <johnlaw.po@gmail.com>
