[main][Automation] Update versions (#4773)

These files are used for picking agent versions in integration tests.

The content is based on responses from https://www.elastic.co/api/product_versions and https://snapshots.elastic.co

The current update is generated based on the following requirements:

Package version: 8.15.0

```json
{
  "UpgradeToVersion": "8.15.0",
  "CurrentMajors": 1,
  "PreviousMajors": 1,
  "PreviousMinors": 2,
  "SnapshotBranches": [
    "8.14",
    "8.13",
    "7.17"
  ]
}
```

Co-authored-by: obltmachine <150269514+obltmachine@users.noreply.github.com>
Co-authored-by: Denis <denis.rechkunov@elastic.co>
Co-authored-by: Craig MacKenzie <craig.mackenzie@elastic.co>

Author: 4 people

.agent-versions.json

@@ -4,6 +4,7 @@
     "8.13.5-SNAPSHOT",
     "8.13.4",
     "8.12.2",
+    "7.17.22-SNAPSHOT",
     "7.17.21"
   ]
 }

.package-version

@@ -1 +1 @@
-8.15.0
+8.15.0