Changes dbt snapshot solid's "models" config to "select".
Intended to resolve GitHub issue #3818. Although they behave similarly, the dbt CLI options --models and --select are not common across all dbt commands. In the case of the command dbt snapshot, --select exists but --models does not.
A test case has been added for dagster_dbt.dbt_cli_snapshot when extra config fields are used.
Test Plan: buildkite
Reviewers: rexledesma, sidkmenon, sandyryza
Reviewed By: rexledesma
Differential Revision: https://dagster.phacility.com/D6876