Add CURLStringFile class which works similarly to CURLFile, but
uploads a file from a string rather than a file. This avoids the
need to create a temporary file, or use of a data:// stream.
Basic usage:
$file = new CURLStringFile($data, 'filename.txt', 'text/plain');
curl_setopt($curl, CURLOPT_POSTFIELDS, ['file' => $file]);
Closes GH-6456.
The hash is used to check whether the arginfo file needs to be
regenerated. PHP-Parser will only be downloaded if this is actually
necessary.
This ensures that release artifacts will never try to regenerate
stubs and thus fetch PHP-Parser, as long as you do not modify any
files.
Closes GH-5739.
