[IMP] core: update werkzeug dep to 0.16

allows having DeprecationWarnings pop up on runbot

requirements.txt

@@ -40,7 +40,7 @@ requests==2.21.0
 zeep==3.2.0
 python-stdnum==1.8
 vobject==0.9.6.1
-Werkzeug==0.14.1
+Werkzeug==0.16.1
 XlsxWriter==1.1.2
 xlwt==1.3.*
 xlrd==1.1.0