library: arma3client: fix 'Proton: Need a Verb' error
library: arma3client: fix 'Proton: Need a Verb' error

Manifest file got changed for Proton 5.13, now it doesn't contain
exact argument to run Proton, instead '%verb%' is provided
fixes #134

muttleyxd/arma3-unix-launcher,muttleyxd/arma3-unix-launcher