Add Vote enum for upvotes

lib/client/v1/comment_endpoint.dart

@@ -73,7 +73,7 @@ extension CommentEndpoint on V1 {
   /// https://dev.lemmy.ml/docs/contributing_websocket_http_api.html#create-comment-like
   String createCommentLike({
     @required int commentId,
-    @required int score,
+    @required Vote score,
     @required String auth,
   }) {
     throw UnimplementedError();

lib/client/v1/main.dart

@@ -29,3 +29,22 @@ class V1 {
     throw UnimplementedError();
   }
 }
+
+enum Vote {
+  up,
+  none,
+  down,
+}
+
+extension VoteValue on Vote {
+  int get value {
+    switch (this) {
+      case Vote.up:
+        return 1;
+      case Vote.none:
+        return 0;
+      case Vote.down:
+        return -1;
+    }
+  }
+}

lib/client/v1/post_endpoint.dart

@@ -42,7 +42,7 @@ extension PostEndpoint on V1 {
   /// https://dev.lemmy.ml/docs/contributing_websocket_http_api.html#create-post-like
   String createPostLike({
     @required int postId,
-    @required int score,
+    @required Vote score,
     @required String auth,
   }) {
     throw UnimplementedError();