Update copyright year to the current year

[Vadim-Khristenko]

The copyright year mentioned in the repository needs to be updated to reflect the current year.

aiogram-3-guide/mkdocs.yml

Line 15 in 6cb3283

copyright: Copyright © 2020-2024 Groosha

[MasterGroosha]

That’s an interesting one.
On the one hand, that’s normal to automatically update copyright year on build:
squidfunk/mkdocs-material#4969

On the other hand, I believe that copyright years should reflect time period, when website was actively updated. For example, if there were no meaningful changes this year, copyright should not be updated.