ci: group codeql-action sub-actions in Dependabot

Dependabot creates separate PRs for each codeql-action sub-action
(init, analyze, upload-sarif) because they share a repo but are treated
as independent dependencies. This causes CI failures due to SHA
version mismatch until someone manually aligns the remaining refs.

Add a Dependabot group so all codeql-action updates land in one PR.

Signed-off-by: Sudip Sinha <Sudip.Sinha@RedHat.com>

Author: SudipSinha

.github/dependabot.yml

@@ -17,6 +17,10 @@ updates:
       - trustyai-explainability/reviewers
     reviewers:
       - trustyai-explainability/reviewers
+    groups:
+      codeql-action:
+        patterns:
+          - "github/codeql-action/*"
 
   - package-ecosystem: "docker"
     directory: "/"