requirements: Lock versions and bump lxml

requirements.txt

@@ -1,16 +1,40 @@
-lxml==4.2.5
-requests==2.20.1
-
+alembic==1.3.1
+amqp==2.5.2
+bdd-tester==0.0.8
+billiard==3.6.1.0
 celery==4.3.0
-redis==3.2.1
-uWSGI==2.0.17.1
-psycopg2==2.7.6.1
-
+certifi==2019.11.28
+chardet==3.0.4
+Click==7.0
+cssmin==0.2.0
 Flask==1.0.2
 Flask-Assets==0.12
 Flask-Migrate==2.3.0
-
-cssmin==0.2.0
+Flask-SQLAlchemy==2.4.1
+gherkin-official==4.1.3
+idna==2.7
+importlib-metadata==1.2.0
+itsdangerous==1.1.0
+Jinja2==2.10.3
 jsmin==2.2.2
+kombu==4.6.7
+lxml==4.6.3
+Mako==1.1.0
+MarkupSafe==1.1.1
+more-itertools==8.0.2
+pkg-resources==0.0.0
+psycopg2==2.7.6.1
+python-dateutil==2.8.1
+python-editor==1.0.4
+pytz==2019.3
+redis==3.2.1
+requests==2.20.1
+six==1.13.0
+SQLAlchemy==1.3.11
+urllib3==1.24.3
+uWSGI==2.0.17.1
+vine==1.3.0
+webassets==0.12.1
+Werkzeug==0.16.0
+zipp==0.6.0
 
-bdd-tester==0.0.8