chore(deps): update dependency google-cloud-spanner-admin-instance-v1 to v2

Author: renovate-bot

google-cloud-spanner/Gemfile

@@ -7,7 +7,7 @@ gem "gapic-common", ">= 0.25.0"
 gem "google-cloud-core", "~> 1.8.0"
 gem "google-cloud-errors", "~> 1.5.0"
 gem "google-cloud-spanner-admin-database-v1", "~> 1.3"
-gem "google-cloud-spanner-admin-instance-v1", "~> 1.5"
+gem "google-cloud-spanner-admin-instance-v1", "~> 2.0"
 gem "google-cloud-spanner-v1", "~> 1.8"
 gem "google-style", "~> 1.31.0"
 gem "grpc", "~> 1.67"