Add support for werkzeug 2.0

issue10086
review337571002
(grafted from 5aad3a917a68bd9a1f876e85aa9381ba7893f4dc)

--HG--
branch : 6.0

setup.py

@@ -60,7 +60,7 @@ else:
 if local_version:
     version += '+' + '.'.join(local_version)
 
-requires = ['elasticsearch', 'python-stdnum >= 1.1.0', 'werkzeug < 2']
+requires = ['elasticsearch', 'python-stdnum >= 1.1.0', 'werkzeug']
 for dep in info.get('depends', []):
     if not re.match(r'(ir|res)(\W|$)', dep):
         requires.append(get_require_version('trytond_%s' % dep))