docs: Add blogpost for 3.3.6 release

[tgodzik]

No description provided.

[WojciechMazur]

We should also modify 2 additional files:

• Update _data/scala-releases.yaml so that it contians 3.3.6 instead of 3.3.5
• Add _downloads/ entry so that we have a dedicated page for downloads of this version

See https://github.com/scala/scala-lang/pull/1728/files

[WojciechMazur]

We should also update to names of the files, the date thats showing for blogposts is taken from the file name, the blogpost should be named _posts/2025-05-08-release-notes-3.3.6.md if we're going to announce it tomorrow

[tgodzik]

@WojciechMazur done and done! We should be good to announce today.

[Gedochao]

LGTM