fix: Fix case for RTCIceCandidate.sdpMLineIndex, close #1.

Author: cloudwebrtc

lib/src/rtc_ice_candidate.dart

@@ -1,13 +1,13 @@
 class RTCIceCandidate {
-  RTCIceCandidate(this.candidate, this.sdpMid, this.sdpMlineIndex);
+  RTCIceCandidate(this.candidate, this.sdpMid, this.sdpMLineIndex);
   final String? candidate;
   final String? sdpMid;
-  final int? sdpMlineIndex;
+  final int? sdpMLineIndex;
   dynamic toMap() {
     return {
       'candidate': candidate,
       'sdpMid': sdpMid,
-      'sdpMLineIndex': sdpMlineIndex
+      'sdpMLineIndex': sdpMLineIndex
     };
   }
 }