Merge pull request #581 from flaskbb/dependabot/pip/urllib3-1.26.4

Bump urllib3 from 1.26.2 to 1.26.4

requirements.txt

@@ -52,7 +52,7 @@ speaklater==1.3
 SQLAlchemy==1.3.20
 SQLAlchemy-Utils==0.36.8
 Unidecode==1.1.1
-urllib3==1.26.2
+urllib3==1.26.4
 vine==5.0.0
 Werkzeug==1.0.1
 Whoosh==2.7.4