chore: sync CODEOWNERS with cnpg-infra policy (#1047)

Regenerates this repo's CODEOWNERS from cloudnative-pg/cnpg-infra's
`componentowners-policy.yaml`, the org's tracked desired state for
CODEOWNERS content.

- Routes ownership through this repo's dedicated GitHub owners team
instead of hardcoded usernames, so membership changes are picked up
automatically.
- Any path-scoped rule now also includes the repo's general owners, so a
path rule adds reviewers rather than silently replacing the `*` rule's
owners for that subtree (CODEOWNERS only honors the last matching
pattern, it does not merge).

See cloudnative-pg/cnpg-infra for the policy this is generated from.

Assisted-by: Claude

Signed-off-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>

CODEOWNERS

@@ -1,5 +1,9 @@
-# The CODEOWNERS file is used to define individuals or teams that are
-# responsible for code in a repository. For details, please refer to
-# https://docs.github.com/en/free-pro-team@latest/github/creating-cloning-and-archiving-repositories/about-code-owners
+# This file is generated from componentowners-policy.yaml in
+# cloudnative-pg/cnpg-infra — do not hand-edit, propose changes there instead.
+#
+# Path-scoped rules below always include the repo's own general owners
+# (the "*" line) in addition to their own specific teams/users, since
+# CODEOWNERS only honors the LAST matching pattern for a given path —
+# it does not merge an earlier, less-specific rule into a later one.
 
-* @leonardoce @mnencia @gbartolini @fcanovai @armru @NiccoloFei
+* @cloudnative-pg/plugin-barman-cloud-owners