dbt-spark v0.19.1rc1

This is a release candidate for a patch release tracking dbt v0.19.1rc1.

$ pip install dbt-spark==0.19.1rc1
# or
$ pip install "dbt-spark[ODBC]==0.19.1rc1"
# or
$ pip install "dbt-spark[PyHive]==0.19.1rc1"