bugfix #2870

Octokit/Http/Connection.cs

@@ -417,7 +417,7 @@ Task<IApiResponse<T>> SendData<T>(
             TimeSpan timeout,
             CancellationToken cancellationToken,
             string twoFactorAuthenticationCode = null,
-            Uri baseAddress = null, 
+            Uri baseAddress = null,
             Func<object, object> preprocessResponseBody = null)
         {
             Ensure.ArgumentNotNull(uri, nameof(uri));
@@ -628,7 +628,8 @@ public async Task<HttpStatusCode> Delete(Uri uri, object data)
                 Method = HttpMethod.Delete,
                 Body = data,
                 BaseAddress = BaseAddress,
-                Endpoint = uri
+                Endpoint = uri,
+                ContentType = "application/json"
             };
             var response = await Run<object>(request, CancellationToken.None).ConfigureAwait(false);
             return response.HttpResponse.StatusCode;
@@ -754,22 +755,22 @@ async Task<IApiResponse<byte[]>> GetRaw(IRequest request)
 
             return new ApiResponse<byte[]>(response, response.Body as byte[]);
         }
-        
+
         async Task<IApiResponse<Stream>> GetRawStream(IRequest request)
         {
             request.Headers.Add("Accept", AcceptHeaders.RawContentMediaType);
             var response = await RunRequest(request, CancellationToken.None).ConfigureAwait(false);
-            
+
             return new ApiResponse<Stream>(response, response.Body as Stream);
         }
 
         async Task<byte[]> StreamToByteArray(Stream stream)
         {
             if (stream is MemoryStream memoryStream)
             {
-                return memoryStream.ToArray();                
+                return memoryStream.ToArray();
             }
-            
+
             using (var ms = new MemoryStream())
             {
                 await stream.CopyToAsync(ms);