Actually, it seems a better way to confirm this is the apt package version and not the dovecot version. The latest one (i.e one which will be in next release) shows this:

root@e4d2eb1cba0b:/app/haraka# apt list --installed 2>/dev/null | grep dovecot-core dovecot-core/bionic-updates,bionic-security,now 1:2.2.33.2-1ubuntu4.7 amd64 [installed]

The current cloudron container has 1:2.2.33.2-1ubuntu4.6