Similar to #1255 and related to #1299, running `desktop-file-validate /usr/share/applications/rustdesk.desktop` on Ubuntu 22.04 returns the following:
```
/usr/share/applications/rustdesk.desktop: error: value "1.2.0" for key "Version" in group "Desktop Entry" is not a known version
/usr/share/applications/rustdesk.desktop: error: required key "Exec" in group "Desktop Action new-window" is not present
```
* "Version" refers to the Freedesktop Specification[1], not the program's one. Given that this was correctly defined in rustdesk-link.desktop, the same value should be used here too.
* The new-window section is missing the `Exec` key. Ubuntu 22.04 refuses to launch from the Activities overview (apps menu) without this key.
[1] https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html
