Fix typo in make libtailscale command

Signed-off-by: Segi <segihovav@gmail.com>

Author: SegiH

README.md

@@ -53,7 +53,7 @@ If you installed Android Studio the tools may not be in your path. To get the
 correct tool path, run `make androidpath` and export the provided path in your
 shell.
 
-You will also need to run `make llibtailscale` to build the Tailscale AAR which is required to build the Android app.
+You will also need to run `make libtailscale` to build the Tailscale AAR which is required to build the Android app.
 
 #### Code Formatting