Merge pull request #1037 from searxng/dependabot/pip/master/flask-2.1.1

Bump flask from 2.0.3 to 2.1.1

requirements.txt

@@ -1,7 +1,7 @@
 certifi==2021.10.8
 babel==2.9.1
 flask-babel==2.0.0
-flask==2.0.3
+flask==2.1.1
 jinja2==3.1.0
 lxml==4.8.0
 pygments==2.11.2