Mike Volpe, a high-profile Boston tech executive, will leave his post as chief marketing officer of cybersecurity company Cybereason Inc. later this summer to take on a CEO role at an unnamed Boston-based startup, he told the Business Journal. The departure comes amid other high-level changes at the SoftBank-backed cybersecurity company, which has already hired another CMO, according to a spokesperson. Boston-based Cybereason has also hired a new chief financial officer — one with IPO experience…