shyaml: deprecate

[branchv]

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Last release/commit was Dec 2020. Broken on modern setuptools without unmerged 0k/shyaml#67

==> Analytics
install: 32 (30 days), 80 (90 days), 274 (365 days)
install-on-request: 32 (30 days), 80 (90 days), 274 (365 days)
build-error: 0 (30 days)

[Copilot]

Pull Request Overview

This PR deprecates the shyaml formula due to it being unmaintained, with the last release in December 2020 and compatibility issues with modern setuptools. The formula is deprecated in favor of yq as an alternative for YAML processing.

• Adds deprecation notice with date, reason, and replacement formula

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