Retry sync fork on failure

src/WingetCreateCore/Common/GitHub.cs

@@ -336,26 +336,24 @@ private async Task<PullRequest> SubmitPRAsync(string packageId, string version,
             var upstreamMasterSha = upstreamMaster.Object.Sha;
 
             Reference newBranch = null;
-            bool forkSyncAttempted = false;
-
             try
             {
                 var retryPolicy = Policy
                     .Handle<ApiException>()
                     .Or<NonFastForwardException>()
+                    .Or<GenericSyncFailureException>()
                     .WaitAndRetryAsync(3, i => TimeSpan.FromSeconds(i));
 
                 await retryPolicy.ExecuteAsync(async () =>
                 {
                     // Related issue: https://github.com/microsoft/winget-create/issues/282
                     // There is a known issue where a reference is unable to be created if the fork is behind by too many commits.
-                    // Always attempt to sync fork during first execution in order to mitigate the possibility of this scenario occurring.
+                    // Always attempt to sync fork in order to mitigate the possibility of this scenario occurring.
                     // If the fork is behind by too many commits, syncing will also fail with a NotFoundException.
                     // Updating the fork can fail if it is a non-fast forward update, but this should not be blocking as pull request submission can still proceed.
                     // If creating a reference fails, that means syncing the fork also failed, therefore the user will need to manually sync their repo regardless.
-                    if (!forkSyncAttempted && submitToFork)
+                    if (submitToFork)
                     {
-                        forkSyncAttempted = true;
                         await this.UpdateForkedRepoWithUpstreamCommits(repo);
                     }