• [apm] feat: Add options.autoPopAfter parameter to pushActivity to prevent never-ending spans (#2459)
• [apm] fix: Use monotonic clock to compute durations (#2441)
• [core] ref: Remove unused sentry_timestamp header (#2458)
• [node] ref: Drop Node v6, add Node v12 to test matrix, move all scripts to Node v12 (#2455)
• [utils] ref: Prevent instantiating unnecessary Date objects in timestampWithMs (#2442)
• [browser] fix: Mark transactions as event.transaction in breadcrumbs correctly