chore(deps): update golang.org/x/sync commit hash to 37e7f08 (#153)

Author: renovate[bot]

go.mod

@@ -4,6 +4,6 @@ require (
 	github.com/fsnotify/fsnotify v1.4.7 // indirect
 	github.com/google/zoekt v0.0.0-20181210185712-6051a18956be
 	golang.org/x/net v0.0.0-20181220204955-927f97764cc3
-	golang.org/x/sync v0.0.0-20181108010431-42b317875d0f // indirect
+	golang.org/x/sync v0.0.0-20181221204124-37e7f081c4d4 // indirect
 	golang.org/x/sys v0.0.0-20181221145928-b4a75ba826a6 // indirect
 )

go.sum

@@ -44,6 +44,7 @@ golang.org/x/net v0.0.0-20181220204955-927f97764cc3/go.mod h1:mL1N/T3taQHkDXs73r
 golang.org/x/oauth2 v0.0.0-20181120190819-8f65e3013eba/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f h1:Bl/8QSvNqXvPGPGXa2z5xUTmV7VDcZyvRZ+QQXkXTZQ=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20181221204124-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180903190138-2b024373dcd9/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181107165924-66b7b1311ac8 h1:YoY1wS6JYVRpIfFngRf2HHo9R9dAne3xbkGOQ5rJXjU=
 golang.org/x/sys v0.0.0-20181107165924-66b7b1311ac8/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=