fix(ci): lockdown gh-pages workflow to sha

[heitorlessa]

Issue number: #133

Summary

Changes

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Converts tag to immutable git sha for gh-pages workflow

User experience

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Checklist

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• Meets tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Is this a breaking change?

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

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