[skip-changelog] fix link validation workflow (#75)

Author: umbynos

docs/usage.md

@@ -56,5 +56,4 @@ The full list of command line options can be obtained with the `-h` option: `./a
 
 For further information you can use the [command reference]
 
-[install]: installation.md
-[command reference]: commands/arduino-fwuploader.md
+[command reference]: https://arduino.github.io/arduino-fwuploader/dev/commands/arduino-fwuploader/