dog: add future deprecation date and note on openssl@3

[cho-m]

• Have you followed the guidelines for contributing?
• Have you ensured that your commits follow the commit style guide?
• Have you checked that there aren't other open pull requests for the same formula update/change?
• Have you built your formula locally with brew install --build-from-source <formula>, where <formula> is the name of the formula you're submitting?
• Is your test running fine brew test <formula>, where <formula> is the name of the formula you're submitting?
• Does your build pass brew audit --strict <formula> (after doing brew install --build-from-source <formula>)? If this is a new formula, does it pass brew audit --new <formula>?

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We could just deprecate on Linux, but probably bad sign if it is still using old versions of packages. Given Rust packages are locked, there is higher risk of security issues that won't get fixed until upstream updates dependencies.

Future date gives 9 months for some activity upstream and 1-2 years afterward before removal.

[BrewTestBot]

🤖 A scheduled task has triggered a merge.

[chenrui333]

relates to ogham/dog#98