Breaking Changes

• PJM requires an api_key on initialization (can be set as PJM_API_KEY environment variable)

Non-Breaking Changes

• Added more methods to the ErcotAPI class which uses the new Ercot API for fetching data
  • Eventually, the ErcotAPI will be the primary way to fetch data from ERCOT, but for now, we still need the Ercot class because the new API doesn't support all datasets.
• Add pjm.get_gen_outages_by_type to get generation outage data
• Flips the congestion sign on NYISO to be consistent with other ISOs. In the NYISO raw data, a negative congestion value means a higher LMP, which is the opposite of other ISOs. We flip the sign so that a negative congestion value means a lower LMP as it does in other ISOs.
• Adds ERCOT unplanned system outages (ERCOT().get_unplanned_system_outages)