[Upgrade] Upgrade the plugin to compatible with Bamboo Version 8.x.x

[LI JIAXIANG]

Hi Mathieu, 

Thanks for your effort on this app. 

Currently, we are exploring to upgrade our bamboo to version 8. I found that the Slack App is incompatible with the version8 so far. Is there any timeline on the upgrading of the APP to compatible with bamboo version 8? 

Thanks and regards,

Jiaxiang

[Adam Clauss]

We are looking for this as well.

[Mathieu MARACHE]

Resolved with newly release 1.5.11 version