docs: fix typos in CONTRIBUTING.md
docs: fix typos in CONTRIBUTING.md

walmartlabs/grunt-bump,dan-kushnaryov/grunt-bump,tischler/grunt-bump,blargism/grunt-bump,halkon/grunt-bump,eddiemonge/grunt-bump,XciD/grunt-bump,vojtajina/grunt-bump,legalthings/grunt-bump