chore: replace old spanner teams in metadata and config (#4357)

b/478003109

Author: suztomo

.repo-metadata.json

@@ -13,7 +13,7 @@
   "api_id": "spanner.googleapis.com",
   "library_type": "GAPIC_COMBO",
   "requires_billing": true,
-  "codeowner_team": "@googleapis/spanner-client-libraries-java",
+  "codeowner_team": "@googleapis/spanner-team",
   "excluded_poms": "google-cloud-spanner-bom",
   "issue_tracker": "https://issuetracker.google.com/issues?q=componentid:190851%2B%20status:open",
   "recommended_package": "com.google.cloud.spanner",

generation_config.yaml

@@ -17,7 +17,7 @@ libraries:
     api_id: spanner.googleapis.com
     transport: grpc
     requires_billing: true
-    codeowner_team: '@googleapis/spanner-client-libraries-java'
+    codeowner_team: '@googleapis/spanner-team'
     library_type: GAPIC_COMBO
     excluded_poms: google-cloud-spanner-bom
     recommended_package: com.google.cloud.spanner