itch.io supports GZIP compression for .wasm and .pck files

**Your Godot version:**
3.5

**Issue description:**
Godot docs state that itch.io doesn't provide compression for `.wasm` and `.pck` files, but [itch.io documentation](https://itch.io/docs/creators/html5) states otherwise in "Compressed file types" section.

**URL to the documentation page:**
https://docs.godotengine.org/en/stable/tutorials/export/exporting_for_web.html#serving-the-files
> **Hosts that don't provide on-the-fly compression:** itch.io, GitLab Pages ([supports manual gzip precompression](https://webd97.de/post/gitlab-pages-compression/))