Pyupgrade to Python 3.9 (#4718)

* Pyupgrade to Python 3.9

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

project_euler/problem_050/sol1.py

@@ -15,10 +15,10 @@ contains 21 terms, and is equal to 953.
 Which prime, below one-million, can be written as the sum of the most
 consecutive primes?
 """
-from typing import List
+from __future__ import annotations
 
 
-def prime_sieve(limit: int) -> List[int]:
+def prime_sieve(limit: int) -> list[int]:
     """
     Sieve of Erotosthenes
     Function to return all the prime numbers up to a number 'limit'