Add gmetronome

gmetronome - Metronome and tempo measurement tool with several customization options 
`#c++` `#gtk3`.

https://gitlab.gnome.org/dqpb/gmetronome

README.md

@@ -219,6 +219,7 @@ this list aims to be broader and include apps from various other ecosystems in v
 - [Chromatic](https://github.com/nate-xyz/chromatic) - Instruments tuner `#rust` `#gtk4` `#libadwaita`.
 - [Drum Machine](https://github.com/Revisto/drum-machine) - Drum machine application to create and play drum beats `#python` `#gtk4` `#libadwaita`.
 - [Fretboard](https://apps.gnome.org/Fretboard/) - Software for guitarists to look up guitar chords `#rust` `#gtk4` `#libadwaita` `#gnome`.
+- [gmetronome](https://gitlab.gnome.org/dqpb/gmetronome) - Metronome and tempo measurement tool with several customization options `#c++` `#gtk3`.
 - [Metronome](https://gitlab.gnome.org/World/metronome) - Metronome application that beats the rhythm to keep the tempo `#rust` `#gtk4` `#libadwaita`.
 
 ## Video