Updates codeowners for Cloud Security (#1447)

This PR adds the Ingest docs team as codeowners for Cloud Security files
under `/solutions/security/cloud/`.

Author: natasha-moore-elastic

.github/CODEOWNERS

@@ -47,6 +47,7 @@
 /solutions/observability/get-started/       @elastic/ski-docs
 /solutions/search/                          @elastic/developer-docs
 /solutions/security/                        @elastic/experience-docs
+/solutions/security/cloud/                  @elastic/ingest-docs
 
 /troubleshoot/                              @elastic/docs
 /troubleshoot/deployments/                  @elastic/admin-docs