Increasing library default timeout (#1005)

# What this PR does

## Which issue(s) this PR fixes

Issues: https://github.com/grafana/oncall/issues/990

## Checklist

- [X] Tests updated

tools/pagerduty-migrator/migrator/__main__.py

@@ -34,6 +34,7 @@ from migrator.resources.users import (
 
 def main() -> None:
     session = APISession(PAGERDUTY_API_TOKEN)
+    session.timeout = 20
 
     print("▶ Fetching users...")
     users = session.list_all("users", params={"include[]": "notification_rules"})