Prepare for creation of 7.16 release branch (#1611)

Removed changes from:
- etc/packages.yml

(selectively cherry picked from commit 95d7e9b6f5)

.github/workflows/backport.yml

@@ -55,7 +55,7 @@ jobs:
     strategy:
       max-parallel: 1
       matrix:
-        target_branch: [7.13, 7.14, 7.15]
+        target_branch: [7.13, 7.14, 7.15, 7.16]
 
     steps:
       - name: Checkout repo

.github/workflows/lock-versions.yml

@@ -5,7 +5,7 @@ on:
         branches:
           description: 'List of branches to lock versions (ordered, comma separated)'
           required: true
-          default: '7.13,7.14,7.15'
+          default: '7.13,7.14,7.15,7.16'
 
 jobs:
   pr: