Update README.md (#4533)
Update README.md (#4533)

Current link to pandas icon is broken.

Co-authored-by: Austin Ziech Robinson <5fd6c9d20207c473940d1e9c063d1006683aa2fe@users.noreply.github.com>
great-expectations/great_expectations,great-expectations/great_expectations,great-expectations/great_expectations,great-expectations/great_expectations