feat: tag most recently released commit as 'latest'

[nayib-jose-gloria]

Reason for Change

• Allow frontend consumers to get the latest release (without needing to make code changes to pin to a specific version), by providing a 'latest' tag that gets reassigned to the HEAD of main whenever a PyPI release occurs.

Changes

• update release GHA to add a step to reassign the 'latest' tag immediately following a successful PyPI release

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 84.62%. Comparing base (f0066a5) to head (cfdec51).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #163 +/- ## ======================================= Coverage 84.62% 84.62% ======================================= Files 19 19 Lines 969 969 Branches 186 186 ======================================= Hits 820 820 Misses 139 139 Partials 10 10 ``` | [Flag](https://app.codecov.io/gh/chanzuckerberg/cellxgene-ontology-guide/pull/163/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/chanzuckerberg/cellxgene-ontology-guide/pull/163/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg) | `84.62% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg#carryforward-flags-in-the-pull-request-comment) to find out more.

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[Bento007]

does this close out https://github.com/chanzuckerberg/cellxgene-ontology-guide/issues/158?