gluebuddy: Add gitlab project bot for the signstar project

This will be used for issue-bot[1][2].

[1] signstar#20 (comment 201743)
[2] https://gitlab.com/gitlab-org/distribution/issue-bot

roles/gluebuddy/defaults/main.yml

@@ -10,3 +10,4 @@ gitlab_bots:
   - project_10185_bot_6f3a8a11922b9008fcb92024361b10b6
   - project_19709_bot_ab88a35474b62399f347877ec82018ac
   - group_11323_bot_c1f9e22ef6391b32e45f7e4a135ecc91
+  - project_16_bot_32e6f4728202b8f9259313830e9e5a18