Update `yyyymmdd` column in `blink_features.features` table

[tunetheweb]

I think this is the last table with a yyyymmdd column instead of date column (despite it being a date).

We fixed blink_features.usage in #39 so can we update blink_features.features too?

[max-ostapenko]

I've removed the features table here #39

[tunetheweb]

Ah OK. Yeah that makes sense. Closing.