chore: reverted changes for urlib3 version, dependabot suggested an incorrect update (#289)

Author: PureDreamer

requirements.txt

@@ -112,7 +112,7 @@ stevedore==3.2.2
 traitlets==5.0.4
 typed-ast==1.4.1
 typing-extensions==3.7.4.3
-urllib3==1.26.5
+urllib3==1.25.10
 vine==5.0.0
 wcwidth==0.2.5
 Werkzeug==1.0.1