Do the dots (...) keep being added, even if they are being added slowly?
If the number of dots is increasing then it means the process is continuing.
It shouldn’t be taking that long though so your server might be experiencing some latency either when processing the hashes file or reading/writing the files.
If literally nothing is happening then it might be an issue with the JavaScript and refreshing the page may help, though you may need to keep doing it until the process is finished.
Failing that, as someone suggested, uploading the files manually would work. Once it is done just go straight to the install URL to complete the upgrade.