Added changelog.
Added changelog.

alfredodeza/pytest,The-Compiler/pytest,nicoddemus/pytest,markshao/pytest,pfctdayelise/pytest,tomviner/pytest,pytest-dev/pytest,ddboline/pytest,tomviner/pytest,RonnyPfannschmidt/pytest,davidszotten/pytest,hackebrot/pytest,Akasurde/pytest,nicoddemus/pytest,txomon/pytest,The-Compiler/pytest