add test and change code using date transformation [0.25h+0.25h]

[epogrebnyak]

ssg-dataset/src/ssg/github.py

Lines 67 to 68 in 3124f9c

	def date_only(s):
	return s[: 4 + 2 + 2 + 2] # TODO: change to date

This function cuts a date out of longer string just as first several chcracter in a string, It works, bitnot clean.

• create test_date-only() in test_github.py
• suggest code chage for this function

[epogrebnyak]

possible fix

#! poetry add arrow
def date_only(s: str) -> datetime.date:
  return arrow.get(s).date()