chore: release 4.2.2

[hogan-yuan]

Summary

Bump version to 4.2.2 and add CHANGELOG entry.

Changes in 4.2.2

Fixed

• All languages: CalendarEventsResponse now exposes next_date cursor — callers can pass it as start (with the same end) to fetch the next page of /v1/quote/finance_calendar results
• All languages: CalendarEventInfo.symbol now returns standard symbol format (e.g. CRM.US) instead of raw counter_id format (e.g. ST/US/CRM)

Related

• PR fix(calendar): expose next_date cursor in finance_calendar response #532