switch to Base64Url encoding for certhashes

multiaddr_test.go

@@ -547,7 +547,7 @@ func TestRoundTrip(t *testing.T) {
 		"/ip4/127.0.0.1/tcp/123/tls",
 		"/ip4/127.0.0.1/udp/123",
 		"/ip4/127.0.0.1/udp/123/ip6/::",
-		"/ip4/127.0.0.1/udp/1234/quic/webtransport/certhash/zQmbWTwYGcmdyK9CYfNBcfs9nhZs17a6FQ4Y8oea278xx41",
+		"/ip4/127.0.0.1/udp/1234/quic/webtransport/certhash/uEiDDq4_xNyDorZBH3TlGazyJdOWSwvo4PUo5YHFMrvDE8g",
 		"/p2p/QmbHVEEepCi7rn7VL7Exxpd2Ci9NNB6ifvqwhsrbRMgQFP",
 		"/p2p/QmbHVEEepCi7rn7VL7Exxpd2Ci9NNB6ifvqwhsrbRMgQFP/unix/a/b/c",
 	} {

transcoders.go

@@ -389,5 +389,5 @@ func certHashStB(s string) ([]byte, error) {
 }
 
 func certHashBtS(b []byte) (string, error) {
-	return multibase.Encode(multibase.Base58BTC, b)
+	return multibase.Encode(multibase.Base64url, b)
 }