Update dependency requests to v2.25.0

Author: renovate-bot

requirements.txt

@@ -8,7 +8,7 @@ PyMySQL==0.10.0
 python-dateutil==2.8.1
 python-dotenv==0.14.0
 pytz==2020.1
-requests==2.24.0
+requests==2.25.0
 six==1.15.0
 SQLAlchemy==1.3.19
 urllib3==1.25.10