* upstream/master: (122 commits)
  add missing , and article in error message (pydata#2557)
  Add libnetcdf, libhdf5, pydap and cfgrib to xarray.show_versions() (pydata#2555)
  revert to dev version for 0.11.1
  Release xarray v0.11
  DOC: update whatsnew for xarray 0.11 release (pydata#2548)
  Drop the hack needed to use CachingFileManager as we don't use it anymore. (pydata#2544)
  add full test env for py37 ci env (pydata#2545)
  Remove old-style resample example in documentation (pydata#2543)
  Stop loading tutorial data by default (pydata#2538)
  Remove the old syntax for resample. (pydata#2541)
  Remove use of deprecated, unused keyword. (pydata#2540)
  Deprecate inplace (pydata#2524)
  Zarr chunking (GH2300) (pydata#2487)
  Include multidimensional stacking groupby in docs (pydata#2493) (pydata#2536)
  Switch enable_cftimeindex to True by default (pydata#2516)
  Raise more informative error when converting tuples to Variable. (pydata#2523)
  Global option to always keep/discard attrs on operations (pydata#2482)
  Remove tests where answers change in cftime 1.0.2.1 (pydata#2522)
  Finish deprecation cycle for DataArray.__contains__ checking array values (pydata#2520)
  Fix bug where OverflowError is not being raised (pydata#2519)
  ...