1. Locked the WTForms to 2.2.1 to address the import issue with
wtforms.widgets.HTMLString. WTForms 2.3.0 was released on
April 21/2020. This release causes shipyard gate fail with
import error for wtforms.widgets.HTMLString.
2. Deleted psycopg2==2.7.7, which is installed as a dependency of
apache-airflow extra package postgres, and resoted the newer
release psycopg2-binary==2.8.4, to be used instead.
Change-Id: I303a2c94ec409e97af1192ae892b8148fcdbb8d5
0091670583