I know Juanito is very busy. So in the meantime I have apparently succeeded in making an update. I will look at front end, which won't need Juanito's permission to submit.
in the meantime here is possible proof your cam is supported
/usr/local/lib/libgphoto2/print-camera-list human-readable | grep GH5
1754|ptp2 |PTP |Panasonic DC-GH5
There are a couple of possibilities.
If you are impatient, send me a pm....and I can link you to the unofficial packages or just the build script.
Altho I tried to cheat off the existing build script here
http://repo.tinycorelinux.net/6.x/x86_64/tcz/src/libgphoto2/compile_libgphoto2I had errors until I loaded more packages and so if you do want to build your own package and update your self you may like to know this is the amended build deps
compiletc submitqc libexif-dev libtool-dev libusb-dev libxml2-dev libjpeg-turbo-dev liblzma-dev
also I need to find an old digital camera to test that my build actually works but I like the look of gtkam for that purpose.
Other possibles are: Juanito who is very busy may like you to become the maintainer or he may like to me to have a go etc etc.
blowing my own trumpet, I much prefer to ask to submit only if I can test the update works correctly.
Let me know your thoughts if you wish or ignore them which is also OK.
EDIT
I forgot to mention that if like to test out my build, I can offer locales and man pages packages too.