Update golang.org/x/sync commit hash to 09787c9

go.mod

@@ -8,6 +8,6 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/oschwald/geoip2-golang v1.4.0
 	github.com/prometheus/client_golang v1.8.0
-	golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9
+	golang.org/x/sync 09787c993a3a
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 )