add no_parallel marker to modflow_devtools.markers to skip test if xdist is activated
add name_map param to has_pkg() function and requires_pkg marker — accommodate packages which don't have a correspondingly named top-level module, e.g. pytext-xdist -> xdist, mfpymake -> pymake
no_parallelmarker tomodflow_devtools.markersto skip test if xdist is activatedname_mapparam tohas_pkg()function andrequires_pkgmarker — accommodate packages which don't have a correspondingly named top-level module, e.g.pytext-xdist->xdist,mfpymake->pymakehas_pkg()and update docstrings