add pygments dependency because of rst-lint
add pygments dependency because of rst-lint

malinoff/pytest,hackebrot/pytest,pfctdayelise/pytest,nicoddemus/pytest,alfredodeza/pytest,txomon/pytest,davidszotten/pytest,skylarjhdownes/pytest,etataurov/pytest,nicoddemus/pytest,tomviner/pytest,markshao/pytest,jaraco/pytest,eli-b/pytest,Akasurde/pytest,tomviner/pytest,The-Compiler/pytest,rmfitzpatrick/pytest,flub/pytest,MichaelAquilina/pytest,The-Compiler/pytest,pytest-dev/pytest,vmalloc/dessert,tgoodlet/pytest,RonnyPfannschmidt/pytest,tareqalayan/pytest,ddboline/pytest