fix: consider months and days in `years_old` (#11234)

* fix: do not consider months in `calculate_age`

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update get_top_billionaires.py

* Update get_top_billionaires.py

* Update get_top_billionaires.py

* TODAY = datetime.utcnow()

* Update get_top_billionaires.py

* Update build.yml

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>