v5.21.0

Changes

• FEAT: auto-attach boundary events to the active element (bpmn-io/bpmn-js-create-append-anything#64)
• FIX: correctly handle falsy variable atomicValue in editor intelligence (bpmn-io/variable-resolver#68)
• FIX: ensure outline always shows on canvas (bpmn-io/diagram-js#1011)
• DEPS: update to @bpmn-io/properties-panel@3.39.0
• DEPS: update to bpmn-js-create-append-anything@1.2.0
• DEPS: update to diagram-js@15.9.1