Update vendor directory

vendor/golang.org/x/net/proxy/per_host.go

@@ -5,6 +5,7 @@
 package proxy
 
 import (
+	"context"
 	"net"
 	"strings"
 )
@@ -41,6 +42,20 @@ func (p *PerHost) Dial(network, addr string) (c net.Conn, err error) {
 	return p.dialerForRequest(host).Dial(network, addr)
 }
 
+// DialContext connects to the address addr on the given network through either
+// defaultDialer or bypass.
+func (p *PerHost) DialContext(ctx context.Context, network, addr string) (c net.Conn, err error) {
+	host, _, err := net.SplitHostPort(addr)
+	if err != nil {
+		return nil, err
+	}
+	d := p.dialerForRequest(host)
+	if x, ok := d.(ContextDialer); ok {
+		return x.DialContext(ctx, network, addr)
+	}
+	return dialContext(ctx, d, network, addr)
+}
+
 func (p *PerHost) dialerForRequest(host string) Dialer {
 	if ip := net.ParseIP(host); ip != nil {
 		for _, net := range p.bypassNetworks {