Update development documentation to reflect change in workflow artifacts

The "Arduino IDE" workflow was updated to produce individual artifacts for each operating system, but the development
documentation was not updated accordingly at that time.

Author: per1234

Diff for: BUILDING.md

@@ -61,7 +61,7 @@ yarn start
 
 This project is built on [GitHub Actions](https://github.com/arduino/arduino-ide/actions).
 
- - _Snapshot_ builds run when changes are pushed to the `main` branch, or when a PR is created against the `main` branch. For the sake of the review and verification process, the build artifacts can be downloaded from the GitHub Actions page. Note: [due to a limitation](https://github.com/actions/upload-artifact/issues/80#issuecomment-630030144) with the GH Actions UI, you cannot download a particular build, but you have to get all together inside the `build-artifacts.zip`.
+ - _Snapshot_ builds run when changes are pushed to the `main` branch, or when a PR is created against the `main` branch. For the sake of the review and verification process, the build artifacts for each operating system can be downloaded from the GitHub Actions page.
  - _Nightly_ builds run every day at 03:00 GMT from the `main` branch.
  - _Release_ builds run when a new tag is pushed to the remote. The tag must follow the [semver](https://semver.org/). For instance, `1.2.3` is a correct tag, but `v2.3.4` won't work. Steps to trigger a new release build:
    - Create a local tag: