chore(deps): update ghcr.io/cloudnative-pg/postgresql docker tag to v16.4

Author: renovate[bot]

.github/workflows/build.yaml

@@ -18,7 +18,7 @@ jobs:
         include:
           - postgres_version: "16"
             # renovate datasource=docker depName=ghcr.io/cloudnative-pg/postgresql
-            cnpg_version: 16.3-7
+            cnpg_version: 16.4-7
             latest: "true"
           - postgres_version: "15"
             # renovate datasource=docker depName=ghcr.io/cloudnative-pg/postgresql