netcdf encoding "significant_digits" rather than least_significant_digit

[axelschweiger]

Is your feature request related to a problem?

The most current version of xarray only seems to support the "least_significant_digit" compression. As of version 1.6.0. of netcdf4-python, thee option to specify "significant_digits" is available. This allows specifying the total number of digits rather than the digits after the the decimal point and is therefore independent of magnitude.
https://unidata.github.io/netcdf4-python/#Variable.quantization

Describe the solution you'd like

Allow

ncoding={myvar:{'dtype':'float32', 'zlib': True, 'complevel':5, 'significant_digit':7},
                      'time':{'units': 'days since 1800-01-01'}}

Describe alternatives you've considered

No response

Additional context

No response

[nishtha981]

Hey!
I'm an Outreachy applicant. Can I be assigned this issue?

[keewis]

we don't usually assign issues, so you're free to just submit a pull request (don't forget to add tests that verify the new encoding actually works, though)

[dcherian]

There are some in-progress PRs that might fix this as a side effect, but thanks for chekcing @nishtha981 !