Merge pull request #2383 from searxng/dependabot/pip/master/flask-2.3.1

Bump flask from 2.2.3 to 2.3.1

requirements.txt

@@ -1,7 +1,7 @@
 certifi==2022.12.7
 babel==2.12.1
 flask-babel==3.1.0
-flask==2.2.3
+flask==2.3.1
 jinja2==3.1.2
 lxml==4.9.2
 pygments==2.15.1