[AIRFLOW-4900] Resolve incompatible version of Werkzeug (#5535)
[AIRFLOW-4900] Resolve incompatible version of Werkzeug (#5535)

* [AIRFLOW-4900] Resolve incompatible version of Werkzeug

Pin Werkzeug version to >= 0.15 as flask requirement needs it.

* Update setup.py

bolkedebruin/airflow,airbnb/airflow,bolkedebruin/airflow,nathanielvarona/airflow,dhuang/incubator-airflow,dhuang/incubator-airflow,sekikn/incubator-airflow,danielvdende/incubator-airflow,apache/airflow,apache/incubator-airflow,danielvdende/incubator-airflow,sekikn/incubator-airflow,sekikn/incubator-airflow,mrkm4ntr/incubator-airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,sekikn/incubator-airflow,Acehaidrey/incubator-airflow,danielvdende/incubator-airflow,Fokko/incubator-airflow,nathanielvarona/airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,apache/incubator-airflow,wileeam/airflow,mistercrunch/airflow,mistercrunch/airflow,mtagle/airflow,wooga/airflow,cfei18/incubator-airflow,lyft/incubator-airflow,cfei18/incubator-airflow,Fokko/incubator-airflow,mtagle/airflow,apache/incubator-airflow,danielvdende/incubator-airflow,Fokko/incubator-airflow,cfei18/incubator-airflow,wooga/airflow,mistercrunch/airflow,spektom/incubator-airflow,mtagle/airflow,airbnb/airflow,lyft/incubator-airflow,DinoCow/airflow,airbnb/airflow,wileeam/airflow,spektom/incubator-airflow,apache/incubator-airflow,bolkedebruin/airflow,airbnb/airflow,wileeam/airflow,Fokko/incubator-airflow,mrkm4ntr/incubator-airflow,Acehaidrey/incubator-airflow,apache/airflow,DinoCow/airflow,nathanielvarona/airflow,nathanielvarona/airflow,bolkedebruin/airflow,mrkm4ntr/incubator-airflow,cfei18/incubator-airflow,apache/airflow,Acehaidrey/incubator-airflow,DinoCow/airflow,lyft/incubator-airflow,mrkm4ntr/incubator-airflow,mtagle/airflow,apache/airflow,apache/airflow,Acehaidrey/incubator-airflow,wooga/airflow,wileeam/airflow,wooga/airflow,danielvdende/incubator-airflow,dhuang/incubator-airflow,apache/airflow,nathanielvarona/airflow,bolkedebruin/airflow,lyft/incubator-airflow,mistercrunch/airflow,cfei18/incubator-airflow,spektom/incubator-airflow,cfei18/incubator-airflow,spektom/incubator-airflow,dhuang/incubator-airflow,DinoCow/airflow