Update sites.yml

[biegiem]

This PR is:

• Adding a new domain
• Updating existing domain size
• Changing domain name
• Removing existing domain from list
• Website code changes (512kb.club site)
• Other not listed

• I used the uncompressed size of the site
• I have included a link to the GTMetrix report
• The domain is in the correct alphabetical order
• This site is not a ultra lightweight site
• The following information is filled identical to the data file

I confirm that I have read the FAQ section, particularly the two red items around minimal pages and inappropriate content and I attest that this site is neither of these things.

• Check to confirm

- domain: magicznylas.pl
  url: https://www.magicznylas.pl/
  size: 42.1
  last_checked: 2023-07-01

GTMetrix Report: https://gtmetrix.com/reports/www.magicznylas.pl/hlbbjU3W/

[garritfra]

Thanks!