Updates an existing package by name

<package>
	<name>Firefox.dmg</name>
	<category>Unknown</category>
	<filename>Firefox.dmg</filename>
	<info>string</info>
	<notes>string</notes>
	<priority>5</priority>
	<reboot_required>true</reboot_required>
	<fill_user_template>true</fill_user_template>
	<fill_existing_users>true</fill_existing_users>
	<boot_volume_required>true</boot_volume_required>
	<allow_uninstalled>true</allow_uninstalled>
	<os_requirements>string</os_requirements>
	<required_processor>None</required_processor>
	<switch_with_package>Do Not Install</switch_with_package>
	<install_if_reported_available>true</install_if_reported_available>
	<reinstall_option>Do Not Reinstall</reinstall_option>
	<triggering_files>string</triggering_files>
	<send_notification>true</send_notification>
</package>