Update flask_wtf version to work with werkzeug>=1.0 (#11939)
Update flask_wtf version to work with werkzeug>=1.0 (#11939)

Werkzeug 0.16 deprecated werkzeug.url_encode, and removed it in 1.0, so
we need the fixed version of flask_wtf
apache/airflow,apache/incubator-airflow,danielvdende/incubator-airflow,mistercrunch/airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,DinoCow/airflow,cfei18/incubator-airflow,nathanielvarona/airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,dhuang/incubator-airflow,airbnb/airflow,sekikn/incubator-airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,Acehaidrey/incubator-airflow,lyft/incubator-airflow,bolkedebruin/airflow,airbnb/airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,bolkedebruin/airflow,nathanielvarona/airflow,nathanielvarona/airflow,apache/airflow,dhuang/incubator-airflow,mistercrunch/airflow,airbnb/airflow,bolkedebruin/airflow,bolkedebruin/airflow,mrkm4ntr/incubator-airflow,bolkedebruin/airflow,apache/airflow,sekikn/incubator-airflow,DinoCow/airflow,DinoCow/airflow,Acehaidrey/incubator-airflow,cfei18/incubator-airflow,lyft/incubator-airflow,lyft/incubator-airflow,apache/incubator-airflow,apache/airflow,danielvdende/incubator-airflow,mrkm4ntr/incubator-airflow,dhuang/incubator-airflow,mrkm4ntr/incubator-airflow,Acehaidrey/incubator-airflow,mrkm4ntr/incubator-airflow,cfei18/incubator-airflow,sekikn/incubator-airflow,sekikn/incubator-airflow,nathanielvarona/airflow,danielvdende/incubator-airflow,Acehaidrey/incubator-airflow,dhuang/incubator-airflow,mistercrunch/airflow,airbnb/airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,DinoCow/airflow,apache/airflow,cfei18/incubator-airflow,apache/airflow,mistercrunch/airflow,nathanielvarona/airflow,cfei18/incubator-airflow