The repository was renamed from 011-black-jack to 011-blackjack and the
Gitea organisation from Tirsvad-Udemy-100_days_of_code to
Tirsvad-Udemy-100-days-of-code (kebab-case convention). Update the
milestone and commit links in BC-001, SA-001, PP-001, MIL-001 and
MIL-002, and the organisation name in BC-001.