Update CONTRIBUTING.rst
Update CONTRIBUTING.rst

basic pytest can't handle examples, pass tests dir
fkazimierczak/flask,mitsuhiko/flask,tristanfisher/flask,drewja/flask,pallets/flask,pallets/flask,dawran6/flask,drewja/flask,fkazimierczak/flask,drewja/flask,mitsuhiko/flask,tristanfisher/flask,dawran6/flask,pallets/flask,fkazimierczak/flask