Gist adds or removes capabilities to the PMPro Membership Manager role.

pmpro-add-manager-capabilities.php

add_action( 'admin_init', 'add_roles_to_membership_manager', 22 );
function add_roles_to_membership_manager() {
	$manager = get_role( 'pmpro_membership_manager' );
	if ( $manager ) {
		$manager->add_cap( 'edit_plugins' );
		$manager->add_cap( 'activate_plugins' );
		$manager->add_cap( 'promote_users' );
		$manager->remove_cap( 'pmpro_addons' );
		$manager->remove_cap( 'pmpro_memberslist' );
		$manager->remove_cap( 'remove_users' );
	}
}