release: 1.2.0 (#434)

* refactor(client): deduplicate page response classes (#433)

feat(client): make pagination robust to missing data
docs: add comments for page methods

* refactor(client): migrate pages to builder pattern (#435)

* release: 1.2.0

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Co-authored-by: stainless-app[bot] <142633134+stainless-app[bot]@users.noreply.github.com>