- Gains new `Redshift` driver for connecting to Redshift databases.  
  Redshift databases behave almost identically to Postgres so this
  driver allows downstream packages to distinguish between the two (#258).
- Datetime values are now passed to the database using an unambiguous time zone format (#255, @imlijunda).
- Document `Postgres()` together with `dbConnect()` (#242).
- Windows: update libpq to 12.2.0.