go.mod: update Cloud SQL proxy dependency (#508)

Mostly to pick up fix for GoogleCloudPlatform/cloud-sql-proxy#194

go.mod

@@ -17,7 +17,7 @@ module github.com/google/go-cloud
 require (
 	cloud.google.com/go v0.0.0-20180816152847-43dc61c3e9d0
 	contrib.go.opencensus.io/exporter/stackdriver v0.0.0-20180421005815-665cf5131b71
-	github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20180321230639-1e456b1c68cb
+	github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20180907232109-123a90f520a1
 	github.com/aws/aws-sdk-go v1.13.20
 	github.com/aws/aws-xray-sdk-go v1.0.0-rc.5 // indirect
 	github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 // indirect

go.sum

@@ -4,6 +4,9 @@ contrib.go.opencensus.io/exporter/stackdriver v0.0.0-20180421005815-665cf5131b71
 contrib.go.opencensus.io/exporter/stackdriver v0.0.0-20180421005815-665cf5131b71/go.mod h1:QeFzMJDAw8TXt5+aRaSuE8l5BwaMIOIlaVkBOPRuMuw=
 github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20180321230639-1e456b1c68cb h1:p5Uq1pkf0drOTEMpDFbbcGeFrQXvNAKTSLZtL/5GCO8=
 github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20180321230639-1e456b1c68cb/go.mod h1:aJ4qN3TfrelA6NZ6AXsXRfmEVaYin3EDbSPJrKS8OXo=
+github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20180907232109-123a90f520a1 h1:KrmzxU4oPDaa5JtVofM+dBXXGxTRxjMw6uh3eMO45ig=
+github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20180907232109-123a90f520a1/go.mod h1:aJ4qN3TfrelA6NZ6AXsXRfmEVaYin3EDbSPJrKS8OXo=
+github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20181001173300-3236ed58baeb h1:iJns5Mrt5mMYs7etRovQvNafHrgzwTDqaFHk0AVusp0=
 github.com/aws/aws-sdk-go v1.13.20 h1:86wZR5yeY4bRb7lKN6blkLabklWplUdP/V1vBiY9jNU=
 github.com/aws/aws-sdk-go v1.13.20/go.mod h1:ZRmQr0FajVIyZ4ZzBYKG5P3ZqPz9IHG41ZoMu1ADI3k=
 github.com/aws/aws-xray-sdk-go v1.0.0-rc.5 h1:7a0ES/UQniY+MWQ9TQd2rxzVbeTIFfX9lLGrM+UyNxI=