Prep for next release 8.16 (#3914)

* Prep for Release 8.16

* Add subscription

* Remove double subscription

* Formatting

* Formatting

* Revert Beaconing rules minstack and lock version

Removed changes from:
- detection_rules/etc/packages.yaml

(selectively cherry picked from commit 4245a81)

Author: shashank-elastic

.github/workflows/lock-versions.yml

@@ -6,7 +6,7 @@ on:
           description: 'List of branches to lock versions (ordered, comma separated)'
           required: true
           # 7.17 was intentionally skipped because it was added late and was bug fix only
-          default: '8.9,8.10,8.11,8.12,8.13,8.14'
+          default: '8.10,8.11,8.12,8.13,8.14,8.15'
 
 jobs:
   pr: