Version needs to be set to actual version and not just keyword _latest_

[shaahji]

Version needs to be set to actual version and not just keyword latest

Checklist before requesting a review

• Add unit tests for this change.
• Make sure all tests can pass.
• Update documents if necessary.
• Lint and apply fixes to your code by running lintrunner -a
• Is this a user-facing change? If yes, give a description of this change to be included in the release notes.

(Optional) Issue link

[Copilot]

Pull request overview

Updates the Sphinx documentation configuration so the displayed docs version is a concrete value rather than the placeholder "latest", aligning with the docs versioning approach used by the version switcher.

Changes:

• Set version in docs/source/conf.py from "latest" to "0.12.1".

[Copilot]

version is used as the pydata-sphinx-theme version switcher version_match (see html_theme_options['switcher']['version_match']). On main, this should match the versions.json entry for the root docs (currently "main"), not a pinned release like 0.12.1, otherwise the switcher will not select the current docs version and the site will be mislabeled.

Suggested change

	version = "0.12.1"
	release = version
	release = "0.12.1"
	_docs_version = os.environ.get("READTHEDOCS_VERSION") or os.environ.get("GITHUB_REF_NAME")
	version = "main" if _docs_version == "latest" else (_docs_version or release)