Further patching the negative consumed EF issue

[grgmiller]

When running the pipeline with the newly-downloaded EIA-930 data, it seems that there may have been some retroactive revisions to the 2020 data, because now when outputting consumed emission factors, we are getting an error message about there being negative emission factors when exporting monthly consumed factors for SEC. The root cause of this issue is described by #214, and was patched by #221 (in which we created a list of BAs with this issue and told the pipeline to use the reported demand values from EIA-930 instead of calculating net demand from generation and interchange). SEC was not previously included in this list, but now seems to be exhibiting these same symptoms.

The larger fix to this is captured by #220, but in the meantime, there are a couple ways we can go about patching this.

1. Investigate whether there is a new data quality issue in the EIA-930 timeseries for SEC that we need to correct in eia930.manual_930_adjust()
2. Add SEC to the BA_930_INCONSISTENCY list in src.consumed(). However, since this issue seems to be confined to 2020 data for SEC, I'd like to see us update BA_930_INCONSISTENCY so that we are only applying this patch for years where it is necessary, rather than applying it to these BAs in all years. One way to do this would be to make BA_930_INCONSISTENCY a dictionary, where the key is the year and the value is a list of the BAs that need this patch in that year.

Originally posted by @grgmiller in #259 (comment)