[9.2][Automation] Update versions (#10841)

These files are used for picking the starting (pre-upgrade) or ending (post-upgrade) agent versions in upgrade 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`

```json
{
  "version": "9.2.1-SNAPSHOT",
  "build_id": "9.2.1-a3524b72",
  "manifest_url": "https://snapshots.elastic.co/9.2.1-a3524b72/manifest-9.2.1-SNAPSHOT.json",
  "summary_url": "https://snapshots.elastic.co/9.2.1-a3524b72/summary-9.2.1-SNAPSHOT.html",
  "core_version": "9.2.1",
  "stack_build_id": "9.2.1-a3524b72-SNAPSHOT"
}
```

`testing/integration/testdata/.upgrade-test-agent-versions.yml`

```json
{
  "UpgradeToVersion": "9.2.1",
  "CurrentMajors": 1,
  "PreviousMajors": 1,
  "PreviousMinors": 2,
  "SnapshotBranches": [
    "9.2",
    "9.1",
    "8.19",
    "7.17"
  ]
}
```

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Pierre HILBERT <[email protected]>

Author: github-actions[bot]

.package-version

@@ -1,8 +1,8 @@
 {
-  "version": "9.2.0-SNAPSHOT",
-  "build_id": "9.2.0-35caaf1a",
-  "manifest_url": "https://snapshots.elastic.co/9.2.0-35caaf1a/manifest-9.2.0-SNAPSHOT.json",
-  "summary_url": "https://snapshots.elastic.co/9.2.0-35caaf1a/summary-9.2.0-SNAPSHOT.html",
-  "core_version": "9.2.0",
-  "stack_build_id": "9.2.0-35caaf1a-SNAPSHOT"
+  "version": "9.2.1-SNAPSHOT",
+  "build_id": "9.2.1-a3524b72",
+  "manifest_url": "https://snapshots.elastic.co/9.2.1-a3524b72/manifest-9.2.1-SNAPSHOT.json",
+  "summary_url": "https://snapshots.elastic.co/9.2.1-a3524b72/summary-9.2.1-SNAPSHOT.html",
+  "core_version": "9.2.1",
+  "stack_build_id": "9.2.1-a3524b72-SNAPSHOT"
 }

testing/integration/testdata/.upgrade-test-agent-versions.yml

@@ -5,8 +5,8 @@
 # upgrade integration tests.
 
 testVersions:
+  - 9.1.7-SNAPSHOT
   - 9.1.6
-  - 9.1.6-SNAPSHOT
   - 9.0.8
   - 8.19.6
   - 8.19.6-SNAPSHOT