If you are confident with the command line you can install it manually.
All though the node modules will also need updating
this worked for me on a fresh install of 3.163
If all goes well, when completed it will appear in the installed plugins secton of V3 and you will need to activate it.
sudo apt-get update
sudo apt-get -y install build-essential
cd ~
wget http://plugins.volumio.org/plugins/volumio/armhf/system_controller/gpio-buttons/gpio-buttons.zip
mkdir ./gpio-buttons
miniunzip gpio-buttons.zip -d ./gpio-buttons
cd gpio-buttons
volumio plugin install
## when installation is finalized, press CTRL+C ##
cd /data/plugins/system_controller/gpio-buttons/
npm install --save onoff@6.0.0