ENH : Add Angrist-Krueger QOB (1980 Census) dataset#2

Dijo-404 wants to merge 1 commit intopgmpy:mainpgmpy/example_datasets:mainfrom

Dijo-404:feat/iv-1980-census-extractDijo-404/example_datasets:feat/iv-1980-census-extractCopy head branch name to clipboard