tests cover the secret token validation

Change package minimum php version to 8.0

Update README.md

test: add ReplyKeyboardTest tests

feat: make it extendable

update README.md

feat: add thenDie parameter to listen()

fix: %p added as an equivalent for regex (.*)

sscanf() doesn't parse "Hello world" by %s, because there's a whitespace. I added %p to the parser and the package no longer uses sscanf.

Fix PHP version

Fix a bug