Tinode.isRelativeURL is not a function
Describe the bug Could not download file using web app interface.
To Reproduce Steps to reproduce the behavior:
- Go to chat window
- Click on the file to download
- The progress bar will be stuck
- See error
Expected behavior File should be downloaded successfully.
Screenshots

Environment (please complete the following information):
- OS: Both Windows and MacOS
- Browser: Both Chrome and Safari
- TinodeWeb Version v0.20.0-rc1
- TinodeServer Version v0.20.0-rc1
Console log [15:35:15.492] out: {"note":{"topic":"usrMwpdl99BJbA","what":"read","seq":14}} react-dom.production.min.js:56 Uncaught TypeError: Tinode.isRelativeURL is not a function at De.default.download (tinode.prod.js:1:40637) at zs.downloadFile (attachment.jsx:29:16) at s (attachment.jsx:72:14) at Object.vi (react-dom.production.min.js:202:330) at ui (react-dom.production.min.js:32:27) at xi (react-dom.production.min.js:32:81) at zg (react-dom.production.min.js:55:403) at rg (react-dom.production.min.js:56:317) at react-dom.production.min.js:66:168 at react-dom.production.min.js:240:292
Additional context There is no error message in server side.
Fixed in https://github.com/tinode/tinode-js/commit/b0e036bdb48db940d2e5cd21797f8111e9439a19