doc: fix typo

README.md

@@ -19,7 +19,7 @@ You can download Debian/Ubuntu binaries:
 * [testing](https://download.jitsi.org/testing/) ([instructions](https://jitsi.org/Main/InstallJitsiMeetDebianTestingRepository))
 * [nightly](https://download.jitsi.org/unstable/) ([instructions](https://jitsi.org/Main/InstallJitsiMeetDebianNightlyRepository))
 
-You can get our mobile versoins from here:
+You can get our mobile versions from here:
 * [Android](https://play.google.com/store/apps/details?id=org.jitsi.meet)
 * [iOS](https://itunes.apple.com/us/app/jitsi-meet/id1165103905)