Update vendored Psiphon-Labs/goptlib

- Extend lenient authorization handling to SOCKS4a

vendor/github.com/Psiphon-Labs/goptlib/socks.go

@@ -697,11 +697,17 @@ func readSocks4aConnect(r *bufio.Reader) (req SocksRequest, err error) {
 	}
 	req.Username = string(usernameBytes[:len(usernameBytes)-1])
 
-	req.Args, err = parseClientParameters(req.Username)
-	if err != nil {
-		err = newTemporaryNetError("readSocks4aConnect: Failed to parse client parameters: %s", err.Error())
-		return
-	}
+	// [Psiphon]
+	// Since we don't need pluggable transport parameters and prefer enabling clients to proxy,
+	// don't parse or validate username/password as PT args.
+	/*
+		req.Args, err = parseClientParameters(req.Username)
+		if err != nil {
+			err = newTemporaryNetError("readSocks4aConnect: Failed to parse client parameters: %s", err.Error())
+			return
+		}
+	*/
+	// [Psiphon]
 
 	var host string
 	if rawHostIP[0] == 0 && rawHostIP[1] == 0 && rawHostIP[2] == 0 && rawHostIP[3] != 0 {

vendor/vendor.json

@@ -45,10 +45,10 @@
 			"revisionTime": "2016-08-25T06:51:56Z"
 		},
 		{
-			"checksumSHA1": "Ve6jaI7ogHtTWq8QoTJxQpEaGuQ=",
+			"checksumSHA1": "iMZt2Rw0uicop75ZL/vi9r5/gKA=",
 			"path": "github.com/Psiphon-Labs/goptlib",
-			"revision": "18963be5f9c52609b1dd6960d1370d34e63fc3fb",
-			"revisionTime": "2018-04-26T17:24:40Z"
+			"revision": "c0e32a7a3464402b8b0f772794f621e6cd7fdd1e",
+			"revisionTime": "2020-04-06T16:51:25Z"
 		},
 		{
 			"checksumSHA1": "fkgr70NoN6wYgBTWNjFWZscOnl0=",