Temporary files never closed

[MaxInertia]

The function addFile in middleware.go creates, opens and writes to temporary files but doesn't close them. This might cause problems with long running applications.

Starting at line 194

f, err := ioutil.TempFile(os.TempDir(), fmt.Sprintf("graphql-upload-%s%s", handle.Filename, filepath.Ext(handle.Filename)))
if err != nil {
	return nil, fmt.Errorf("unable to create temp file. reason: %v", err)
}

should have defer f.Close() after the error check