Support for additional values for bandwidth type

Support additional bandwidth types defined in RFC3890 and RFC3556

README.md

@@ -54,6 +54,7 @@ Check out the **[contributing wiki](https://github.com/pion/webrtc/wiki/Contribu
 * [Tarrence van As](https://github.com/tarrencev)
 * [Maxim Oransky](https://github.com/sdfsdhgjkbmnmxc)
 * [Graham King](https://github.com/grahamking/)
+* [Brendan Abolivier](https://github.com/babolivier)
 
 ### License
 MIT License - see [LICENSE](LICENSE) for full text

unmarshal.go

@@ -568,9 +568,11 @@ func unmarshalBandwidth(value string) (*Bandwidth, error) {
 	experimental := strings.HasPrefix(parts[0], "X-")
 	if experimental {
 		parts[0] = strings.TrimPrefix(parts[0], "X-")
-	} else if !anyOf(parts[0], "CT", "AS") {
+	} else if !anyOf(parts[0], "CT", "AS", "TIAS", "RS", "RR") {
 		// Set according to currently registered with IANA
 		// https://tools.ietf.org/html/rfc4566#section-5.8
+		// https://tools.ietf.org/html/rfc3890#section-6.2
+		// https://tools.ietf.org/html/rfc3556#section-2
 		return nil, fmt.Errorf("%w `%v`", errSDPInvalidValue, parts[0])
 	}