ERA5 data formatting fails with data downloaded from CDS

[paulapreuss]

format_windpowerlib and format_pvpowerlib from the era5.py module fail with the error AttributeError: 'DataFrame' object has no attribute 'time' after trying to format data retrieved from the CDS. The CDS data returned by get_era5_data_from_datespan_and_position uses the attribute name valid_time instead of time. Presumably this was changed with the recent CDS API update?

[jenny-nyx]

yes, I also believe this was changed with the recent CDS API update. Check out this pull request for one potential fix. Alternatively can instead call df["valid_time"] instead of df.time

[p-snft]

Thanks for referring to the PR. Does it fix the problem in all the cases or is handling of different dataset different? (Please answer in the PR.)