third_party/py: add wtforms

Change-Id: Iabb4fa35ee9369aa0c6592d18fbe69855edf0c7f
diff --git a/third_party/py/requirements.txt b/third_party/py/requirements.txt
index c619738..02ed586 100644
--- a/third_party/py/requirements.txt
+++ b/third_party/py/requirements.txt
@@ -14,6 +14,7 @@
 Flask-Login==0.4.1
 Flask-OAuthlib==0.9.5
 Flask-SQLAlchemy==2.4.0
+Flask-WTF==0.14.2
 future==0.17.1
 gevent==1.4.0
 greenlet==0.4.15
@@ -41,3 +42,4 @@
 urllib3==1.25.3
 uWSGI==2.0.18
 Werkzeug==0.15.5
+WTForms==2.2.1