update dbt-adapters ref to point to the subdirectory (#1459) (#1460)

Author: mikealfare

dev-requirements.txt

@@ -2,7 +2,7 @@
 # TODO: how to automate switching from develop to version branches?
 git+https://github.com/dbt-labs/dbt-core.git#egg=dbt-core&subdirectory=core
 git+https://github.com/dbt-labs/dbt-common.git
-git+https://github.com/dbt-labs/dbt-adapters.git
+git+https://github.com/dbt-labs/dbt-adapters.git#subdirectory=dbt-adapters
 git+https://github.com/dbt-labs/dbt-adapters.git#subdirectory=dbt-tests-adapter
 # if version 1.x or greater -> pin to major version
 # if version 0.x -> pin to minor