Kill Bill notification plugin apis

'org.kill-bill.billing.plugin:killbill-plugin-api-notification:0.18'

<dependency>
	<groupId>org.kill-bill.billing.plugin</groupId>
	<artifactId>killbill-plugin-api-notification</artifactId>
	<version>0.18</version>
</dependency>

<dependency org="org.kill-bill.billing.plugin" name="killbill-plugin-api-notification" rev="0.18"/>

"org.kill-bill.billing.plugin", "killbill-plugin-api-notification", "0.18"