Update Go module version to 1.18

Fixes https://github.com/nhooyr/websocket/issues/359

go.mod

 module nhooyr.io/websocket
 
-go 1.13
+go 1.18
 
 require (
 	github.com/gin-gonic/gin v1.6.3
-	github.com/gobwas/httphead v0.0.0-20180130184737-2c6c146eadee // indirect
-	github.com/gobwas/pool v0.2.0 // indirect
 	github.com/gobwas/ws v1.0.2
 	github.com/golang/protobuf v1.3.5
 	github.com/google/go-cmp v0.4.0
 	github.com/gorilla/websocket v1.4.1
 	golang.org/x/time v0.0.0-20191024005414-555d28b269f0
 )
+
+require (
+	github.com/gin-contrib/sse v0.1.0 // indirect
+	github.com/go-playground/locales v0.13.0 // indirect
+	github.com/go-playground/universal-translator v0.17.0 // indirect
+	github.com/go-playground/validator/v10 v10.2.0 // indirect
+	github.com/gobwas/httphead v0.0.0-20180130184737-2c6c146eadee // indirect
+	github.com/gobwas/pool v0.2.0 // indirect
+	github.com/json-iterator/go v1.1.9 // indirect
+	github.com/leodido/go-urn v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.12 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421 // indirect
+	github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742 // indirect
+	github.com/ugorji/go/codec v1.1.7 // indirect
+	golang.org/x/sys v0.0.0-20200116001909-b77594299b42 // indirect
+	golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 // indirect
+	gopkg.in/yaml.v2 v2.2.8 // indirect
+)

go.sum

@@ -43,7 +43,6 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/ugorji/go v1.1.7 h1:/68gy2h+1mWMrwZFeD1kQialdSzAb432dtpeJ42ovdo=
 github.com/ugorji/go v1.1.7/go.mod h1:kZn38zHttfInRq0xu/PH0az30d+z6vm202qpg1oXVMw=
 github.com/ugorji/go/codec v1.1.7 h1:2SvQaVZ1ouYrrKKwoSk2pzd4A9evlKJb9oTL+OaLUSs=
 github.com/ugorji/go/codec v1.1.7/go.mod h1:Ax+UKWsSmolVDwsd+7N3ZtXu+yMGCf907BLYF3GoBXY=