Add SecretManager block

[ahuang11]

Closes

Example

Screenshots

Checklist

• References any related issue by including "Closes #" or "Closes ".
  • If no issue exists and your change is not a small fix, please create an issue first.
• Includes tests or only affects documentation.
• Passes pre-commit checks.
  • Run pre-commit install && pre-commit run --all locally for formatting and linting.
• Includes screenshots of documentation updates.
  • Run mkdocs serve view documentation locally.
• Summarizes PR's changes in CHANGELOG.md

[desertaxle]

I think it makes sense to have the secret version be an attribute on the block, but still default to latest. Also I think we can just accept a string for the version. I can't think of any time that we'd need to do math with the version number, and we can cast it to an integer if that case does come up.