Breaking changes

Removed TimeGPT class in favor of NixtlaClient.
Removed NixtlaClient.validate_token method in favor of NixtlaClient.validate_api_key.
Removed short-horizon and long-horizon models in favor of timegpt-1 and timegpt-1-long-horizon respectively.
Removed fewshot_steps and fewshot_loss in favor of finetune_steps and finetune_loss respectively.
Removed TIMEGPT_TOKEN environment variable in favor of NIXTLA_API_KEY.
Timestamps in the time_col preserve their type in the outputs (timestamp), previously they were cast to string.
Gaps in series are not filled anymore, in line with our documentation. Please use the fill_gaps function if you require to do so.
NixtlaClient.weights_x is now a list of lists if num_partitions != None, where each element corresponds to the weights for a specific partition.

Features

feat: call v2 endpoints by @jmoralez in #429
feat: orjson serialization by @jmoralez in #452
[FEAT] Add historical exogenous by @elephaint in #453
FEAT: Add feature contributions as attribute and tutorial on how to use by @marcopeix in #448
[FEAT] - Raise error when payload is too large and suggest number of partitions by @marcopeix in #456

fix: removed data input restriction during cross validation finetune by @Yibei990826 in #426

updating excel docs with some more information by @tracykteal in #414
updating FAQ for fee information and Azure being available by @tracykteal in #412
Update 03_excel_addin.ipynb by @tracykteal in #416
[DOC] - Rephrase the sentence for specific loss function by @marcopeix in #436
docs(readme): getting started by @mergenthaler in #438
Adding activate trial link in intro by @tracykteal in #417
[DOC] - Add instructions on saving figures when not working in notebooks by @marcopeix in #454
[BUG]: close img tag in introduction notebook by @marcopeix in #441
docs: add polars quickstart by @jmoralez in #447

Full Changelog: v0.5.2...v0.6.0