adw-gtk3: upgrade 4.7 -> 4.8

Chanelog:
==========
Remove color variable
Use libadwaita style outline border on list rows
Update README.md
Merge pull request openembedded#230 from SamuelBorn/patch-1
Don't style phosh openembedded#231
remove the gtk-4.0 folder from the theme

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-gnome/gnome-themes/adw-gtk3_4.7.bb → meta-oe/recipes-gnome/gnome-themes/adw-gtk3_4.8.bb

@@ -11,6 +11,6 @@ inherit meson
 SRC_URI = "git://github.com/lassekongo83/adw-gtk3.git;protocol=https;branch=main"
 
 S = "${WORKDIR}/git"
-SRCREV = "f5e0807a4572ef6d9ca27042b41211efb41936d2"
+SRCREV = "7ee024ed79f68875e5dea3616be24a703cf72cc5"
 
 FILES:${PN} = "${datadir}/themes"