Add flake8_docstrings to testning requirementst
Add flake8_docstrings to testning requirementst

JelteF/PyLaTeX,votti/PyLaTeX,bjodah/PyLaTeX,ovaskevich/PyLaTeX,sebastianhaas/PyLaTeX,jendas1/PyLaTeX,jendas1/PyLaTeX,votti/PyLaTeX,JelteF/PyLaTeX,bjodah/PyLaTeX,sebastianhaas/PyLaTeX,ovaskevich/PyLaTeX