added progress bar to validator (#2620)
added progress bar to validator (#2620)

Co-authored-by: Peter Hansen <680e4981b1ea0156a93ff8a3ca0d14f19d1586fd@exploredata.com>
Co-authored-by: Eugene Mandel <a36346cb9bda1bc68153ba321ad7fd499805df57@gmail.com>
great-expectations/great_expectations,great-expectations/great_expectations,great-expectations/great_expectations,great-expectations/great_expectations