New style for '::set-output'

[kazie]

Github has done some updates, and this is is a warning, see:
https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Warning: The `set-output` command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

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Second warning:

Node.js 12 actions are deprecated. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/. Please update the following actions to use Node.js 16: actions-rs/toolchain@v1

Not attended, as there is no update of actions-rs/toolchain@v1, seems to be a stale project.
actions-rs/toolchain#219