🎉 TSDB v0.3 coming with new datasets and new feature

We added ETT (Electricity Transformer Temperature) datasets into TSDN and enabled users to migrate cached datasets to a specified location so you can move large cached dataset home dir to your portable disk device.

What's Changed

• Updating README by @WenjieDu in #50
• Adding the ETT dataset by @WenjieDu in #52
• Enable users to migrate tsdb cache data home by @WenjieDu in #53

Full Changelog: v0.2.1...v0.3