Bulk actions to update conversation objects

Editor assessment

The lowercase start is actually spec-conformant — the spec's examples favor lowercase subjects — but 'bulk actions to update conversation objects' is a noun phrase, and 'Add bulk-update endpoints for conversations' would be both imperative and clearer about where the change lands (the API). The body does the essentials: 'Added the endpoints for bulk updating conversation objects' describes the change, and 'Fixes: #3845 #3940 #3943' closes three issues in one footer, which the reference format accommodates. Past tense 'Added' also fights the mood convention. A scope like (conversations) or (api) would help automation, and noting whether the bulk action tolerates partial failure would matter to API consumers. Minor bump is correctly implied; the message is adequate but mood-inconsistent.