Pydaymet

Please check [HISTORY.rst](HISTORY.rst) file for a detailed list
of changes.

Replaced `simplejson` with `orjson` to speed-up JSON operations.

Added `show_versions` for showing versions of the installed deps.

- Retained the compatibility with `xarray` 0.15 by removing the `attrs` flag.
- Replaced `open_dataset` with `load_dataset` for automatic handling of closing the input after reading the content.
- Removed `years` argument from both `byloc` and `bygeom` functions. The `dates` argument now accepts both a tuple of start and end dates and a list of years.
- This release will be a part of Hydrodata 0.7.0.

Initial release.