Add type hints and default args for Project Euler problem 5 (#2982)

* add type hints and default args for problem 5

* Update sol1.py

* Update sol2.py

Co-authored-by: Dhruv <dhruvmanila@gmail.com>

Author: sgalpha01

project_euler/problem_05/sol1.py

@@ -8,7 +8,7 @@
 """
 
 
-def solution(n):
+def solution(n: int = 20) -> int:
     """Returns the smallest positive number that is evenly divisible(divisible
     with no remainder) by all of the numbers from 1 to n.
 

project_euler/problem_05/sol2.py

@@ -9,18 +9,18 @@
 """ Euclidean GCD Algorithm """
 
 
-def gcd(x, y):
+def gcd(x: int, y: int) -> int:
     return x if y == 0 else gcd(y, x % y)
 
 
 """ Using the property lcm*gcd of two numbers = product of them """
 
 
-def lcm(x, y):
+def lcm(x: int, y: int) -> int:
     return (x * y) // gcd(x, y)
 
 
-def solution(n):
+def solution(n: int = 20) -> int:
     """Returns the smallest positive number that is evenly divisible(divisible
     with no remainder) by all of the numbers from 1 to n.