feat: regular expression conjecture #2

Description

a conjecture that checks a value matches a given regular expression pattern.

Context

There is currently support for prefix and suffix matching, but sometimes you need a more complex match.

Possible implementation

assert "foo bar baz" == conjecture.matches_regex(r"\bbar\b")

assert "FOO BAR BAZ" == conjecture.matches_regex(r"\bbar\b", flags=re.IGNORECASE)