Fix crash on Python 3.11.2 due to wrong quoting

[git-developer]

Fixes:

# DISPLAY=:0 ./sc-controller-v0.4.8.20-1-bookworm-x86_64.AppImage
Traceback (most recent call last):
  File "/tmp/.mount_sc-conqJTlym/usr/bin/sc-controller", line 27, in <module>
    from scc.gui.app import App
  File "/tmp/.mount_sc-conqJTlym/usr/lib/python/scc/gui/app.py", line 13, in <module>
    from scc.gui.controller_image import ControllerImage
  File "/tmp/.mount_sc-conqJTlym/usr/lib/python/scc/gui/controller_image.py", line 96
    self.set_image(os.path.join(self.app.imagepath, f"controller-images/{self.current["gui"]["background"]}.svg"))
                                                                                       ^^^
SyntaxError: f-string: unmatched '['

[C0rn3j]

Ah, I might have actually done that elsewhere too, where I converted to f-strings, as my tooling is set up for 3.12+, whoops.

Thanks!

On a related note, I declared 3.9 as minimum (non-EOL versions only, 3.8 is dead next month) in the README so it doesn't just say 3.

I do wonder if the current code would actually run on 3.9, as I tend to add modern typing features where I can, to make the code saner.

[git-developer]

Just for the record:

• Ubuntu Focal: Python 3.8
• Debian Bullseye: Python 3.9
• Ubuntu Jammy: Python 3.10
• Debian Bookworm: Python 3.11