Non-canonical freedesktop path for icon file

[tim77]

Look like the proper place for Minder icon file is scalable folder since it in SVG format.

icons/hicolor/128x128/apps/com.github.phase1geo.minder.svg
to
icons/hicolor/scalable/apps/com.github.phase1geo.minder.svg

Can we try this in order to fix flathub/com.github.phase1geo.minder#40?

"errors": [
    "non-png-icon-in-hicolor-size-folder"

    "non-png-icon-in-hicolor-size-folder: ['/tmp/tmp57ti8txx/icons/hicolor/128x128/apps/com.github.phase1geo.minder.svg', '/tmp/tmp57ti8txx/icons/hicolor/24x24/apps/com.github.phase1geo.minder.svg', '/tmp/tmp57ti8txx/icons/hicolor/64x64/apps/com.github.phase1geo.minder.svg', '/tmp/tmp57ti8txx/icons/hicolor/32x32/apps/com.github.phase1geo.minder.svg', '/tmp/tmp57ti8txx/icons/hicolor/48x48/apps/com.github.phase1geo.minder.svg', '/tmp/tmp57ti8txx/icons/hicolor/16x16/apps/com.github.phase1geo.minder.svg']"
    
"message": "Please consult the documentation at https://docs.flathub.org/docs/for-app-authors/linter"

[phase1geo]

I have fixed this issue in the master branch. It will be generally available in the upcoming 1.17 release.